Parshat Toldot: A Striking Resemblance

Our parsha is filled with drama; Yitzchak and Rivkah struggle with infertility, Yaakov and Esav are born, Yitzchak and Rivkah play favorites with their children, Yaakov convinces Esav to sell him his birthright, famine forces Yitzchak to move his family to Gerar and Yaakov takes Esav's blessing forcing him to flee to Lavan to avoid his brother's wrath.
With the all of the excitement contained within the parsha, one could easily gloss over the first pasuk of the sedra and not notice an apparent redundancy. The pasuk states (Breishit 25:19),

ואלה תולדות יצחק בן אברהם אברהם הוליד את יצחק
And these are the offspring of Yitzchack son of Avraham, Avraham begot Yitzchak.

If Yitzchak is the son of Avraham, of course Avraham begot him; seemingly, the Torah could have done without the final clause of the pasuk!
The Ibn Ezra writes, in an explanation that is most likely the closest to peshat, the simplest understanding, of the pasuk,

ויש אומרים כי טעם הוליד גדל ורבה, כמו יולדו על ברכי יוסף (נ,כג), והעד שאמר וישלחם מעל יצחק בנו
And there are those who say that the meaning of 'begot' is 'raised', like 'they were raised on Yosef's knees'(Breishit 50:23), and the proof is that it says 'he sent them away from Yitzchak his son' (Breishit 25:6)

According to the Ibn Ezra, the first part of the pasuk informs us that Yitzchak was Avraham's son, while the second part tells us that not only was he his son, but he was also raised by him. This second clause is not redundant because Yitzchak is the only one of Avraham's children who was raised by Avraham. All of the others (Yishmael, Zimran, Yakshan, Medan, Midian, Yishbak and Shuach - see Breishit 25:2) were sent away; Yishamel was kicked out of the house with his mother at the urging of Sara and we are told explicitly (25:6) that the other children were sent away to lands in the east.
The following Midrash, quoted by Rashi, paints a completely different picture. Rashi writes,

אברהם הוליד את יצחק - על ידי שכתב הכתוב יצחק בן אברהם הוזקק לומר אברהם הוליד את יצחק, לפי שהיו ליצני הדור אומרים מאבימלך נתעברה שרה, שהרי כמה שנים שהתה עם אברהם ולא נתעברה הימנו, מה עשה הקב"ה, צר קלסתר פניו של יצחק דומה לאברהם, והעידו הכל אברהם הוליד את יצחק, וזהו שכתב כאן יצחק בן אברהם היה, שהרי עדות יש שאברהם הוליד את יצחק:
Since Scripture wrote: 'Yitzchak the son of Avraham,' it had to say: 'Avraham begot Yitzchak,' because the scorners of the generation were saying that Sara had conceived from Avimelech, for she had lived with Avraham for many years and had not conceived from him. What did the Holy One, blessed be He, do? He shaped the features of Yitzchak’s face to resemble Avraham’s, and everyone attested that Avraham had begotten Yitzchak. This is the meaning of what is written here: 'Yitzchak, the son of Avraham,' because here is proof that 'Avraham begot Yitzchak.'

According to Rashi, Sara conceived not long after the incident with Avimelech (Breishit 20). People began to scoff and started rumors that Avimelech was the father of Yitzchak. They began to reason that Avraham and Sara had been married for years and had not been able to have children and after being abducted by Avimelech she suddenly had a child? It must not be Avraham's! In order to dispel this notion, Hashem caused Yitzchak's appearance to starkly resemble Avraham's so that no one could claim that Avimelech was his father.
Rabbi Shlomo Efraim Luntschitz (1550-1619) in his commentary the Kli Yakar has a different take on the Midrash. He writes,

וכדי שלא ימצא המערער מקום לחלוק, ולומר אם יצחק נולד כל כך בקדושה וטהרה א”כ למה יצא ממנו עשו שהיה צד נשים תחת בעליהן, ודאי מאבימלך נתעברה שרה ע”כ נמשך בן אחד אחר טבעה של שרה, והשני אחר טבע אבימלך, כי מטעם זה אמרו רז”ל (ב”מ פז.) שהיה צר קלסתר פניו דומה לאברהם.
In order that the scorner would not find room to argue and say that if Yitzchak was really born with holiness and purity, then how could Esav who hunted women from their husbands have come from him? It must be that Avimelech impregnated Sara. As a result one child (of Yitzchak's) had the nature of Sara and the second one had the nature of Avimelech. It is for this reason that our Rabbis of blessed memory said that Hashem shaped the features of his face to look like Avraham's.

The explanation of Rashi seems to be more rational than that of the Kli Yakar. Rashi intimates that people began to question who Yitzchak's father was around the time he was born and so Hashem quashed those rumors by making Yitzchak look like his father; presumably these changes took place as he matured - it is often hard to tell if babies look like their parents at a young age, but once they get older the resemblances become clearer. According to Rashi, Yitzchak began to resemble his father in a more natural way. However, according to the Kli Yakar people only began to question Yitzchak's lineage once they saw the behavior of his rebellious, amoral, son Esav. The Kli Yakar explains that it was at this point, when Esav attained his less than savory reputation, that God altered Yitzchak's appearance to look like Avraham in order to put to rest all of the rumormongers who claimed Yitzchak could have only been the father of Esav if his father was actually Avimelech; according to the Kli Yakar Yitzchak had a sudden change in physical appearance when he was over 60 years old (Esav was born when Yitzchak was 60 and could have only been recognized as a rebel once he grew up).
Perhaps another lesson can be gleaned from this Kli Yakar. The Kli Yakar wrote that the people began to question the identity of Yitzchak's father once they saw Esav's behavior because they could not believe the grandson of Avraham would behave in such a way. However their hypothesis was disproved when Hashem changed Yitzchak's appearance to make him look like a clone of Avraham. While Hashem dispelled the rumors, the question was never answered - how can it be that Avraham could have a grandson and Yitzchak a son, as evil as Esav? The Kli Yakar never answers the question, but an answer can be found in the following Gemara (Nedarim 81a),

מפני מה אין מצויין ת"ח לצאת ת"ח מבניהן? אמר רב יוסף: שלא יאמרו תורה ירושה היא להם.
Why is it uncommon for Torah scholars to have children whom are also Torah scholars? Rabbi Yosef said: So that they (people) will not say that the Torah is their inheritance

The Gemara observes that Torah scholarship and observance are not dynastic. After all, we hear about many heroes of the Tanach who had children that did not follow in their footsteps (Yishmael, Esav, Moshe's sons, Aharon's sons, the sons of Eli the Kohen Gadol, the sons of Shmuel, many of the sons of David Hamelech, etc.). Rav Yosef answers that the reason why this is such a common occurrence is because Hashem does not want people to think that the Torah is private property, an inheritance passed down from father to son; people should not think that because their parents were not great Torah scholars they do not have a share in Hashem's Torah. Hashem made examples out of certain talmidei chachamim to illustrate this rule. An example of this rule is Esav. How could it be that Avraham had a grandson and Yitzchak a son as wicked as Esav? To teach us that Torah knowledge and leadership are not hereditary. It is within everyone’s grasp - man, woman and child.

The Reconciliation of Avraham's Family: A Lesson For Generations

At the end of Avraham's life, after Sara had passed away, we are told that he took another wife whose name was Keturah, with whom he had an additional six children. The Torah does not tell us anything about Keturah other than her name. Rashi, however, identifies her as Hagar, the mother of Yishmael. Rashi writes (25:1),

קטורה - זו הגר, ונקראת קטורה על שם שנאים מעשיה כקטרת ושקשרה פתחה שלא נזדווגה לאדם מיום שפרשה מאברהם
This is Hagar. She was called Keturah because her deeds were as beautiful as incense (קטורת), and because she tied (קטרה, the Aramaic for“tied”) her opening, for she was not intimate with any man from the day she separated from Abraham.

According to Rashi, Hagar had reformed. She was no longer a rebellious maid who challenged her mistress' authority; her deeds were as fragrant as incense and she had not been with another man since she was sent away from Avraham, perhaps because she anticipated the day when she would reunite with him.
Rashi earlier on in the parsha points out that this reunion was made possible by none other than Yitzchak. When Eliezer returned home with Rivkah we are told that Yitzchak had just returned from a trip to Be'er Lechai Roi. Previously, Be'er Lechai Roi was identified as the place where Hagar had an encounter with angel who promised her that she too, like Sara, would have a son whose descendants would be numerous (16:13-14). Rashi, wondering what Yitzchak was doing in Be'er Lechai Roi writes (24:62),

מבוא באר לחי ראי - שהלך להביא הגר לאברהם אביו שישאנה
Coming from Be’er Lachai Roi: where he had gone to bring Hagar to Abraham his father, that he should marry her

Not only did Avraham and Hagar reunite because of Yitzchak's urging, Yishmael and Yitzchak also were able to smooth things over. When Avraham passes away at the end of the parsha we are told that Yitzchak and Yishmael buried him in Me'arat Ha'machpeila (25:9). Where did Yishmael come from? We have not heard from him since he was kicked out of his father's house. And why would he want to have anything to do with the father who rejected him?
Rabbi Jonathan Sacks, with the help of a Midrash from the Pirkei D'Rabi Eliezer, offers a beautiful explanation. He writes, (Covenant and Conversation, Parshat Chaye Sara 5769, for the full text of article click here),

Not only did Isaac feel guilty about the banishment of Hagar and Ishmael. So did Abraham, according to this interpretation. We know that Abraham did not want to send Ishmael away. The text (Gen. 21: 11) is explicit on this point. But Sarah was insistent, and God told Abraham to listen to her. Throughout the lifetime of Sarah, reconciliation was impossible. After her lifetime, however, Abraham sought her out and brought her back. Hagar did not end her days as an outcast. She returned, in honour, as Abraham's wife. That is why, at Abraham's funeral (he died thirty-eight years after Sarah), Isaac and Ishmael were both present. The divided family was reunited.
There is an extraordinary midrash (Pirkei deRabbi Eliezer, 30) which tells the story of how Ishmael was twice visited by Abraham. On both occasions, Ishmael was not at home. On the first, his wife, not knowing Abraham's identity, refused the stranger bread and water. Ishmael divorced her and married a woman named Fatimah. This time, when Abraham visited, again not disclosing his identity, the woman gave him food and drink. The midrash then says "Abraham stood and prayed before the Holy One, blessed be He, and Ishmael's house became filled with all good things. When Ishmael returned, his wife told him about it, and Ishmael knew that his father still loved him."
There is a story here of immense consequence for our time. Jews and Muslims both trace their descent from Abraham - Jews though Isaac, Muslims through Ishmael. Fatimah is an important figure in Islam. She is the daughter of the prophet.
Beneath the surface of the narrative in Chayei Sarah, the sages read the clues and pieced together a moving story of reconciliation between Abraham and Isaac on the one hand, Hagar and Ishmael on the other. Yes, there was conflict and separation; but that was the beginning, not the end. Between Judaism and Islam there can be friendship and mutual respect. Abraham loved both his sons, and was laid to rest by both. There is hope for the future in this story of the past.

Avraham's Real Estate Negotiations: A Final Test

Many of the meforshim wonder why the Torah needed to go into such great detail when telling us about Avraham's acquisition of a burial plot for Sara. Why not simply tell us that when Sara passed away, Avraham bought Me'arat Ha'machpeila from Ephron?
The classic answered offered by the Midrash (Breishit Rabbah 79:6) is that the Torah wanted the transaction put on record in case anyone ever disputed Bnei Yisrael's claim to the land. The Midrash goes on to say that this explains why we are told that David Hamelech purchased the land that the Beit Hamikdash stood on (Divrei Hayamim I 21:25) and that Yaakov purchased land in Shechem, the eventual burial place of Yosef (Breishit 33:19). Hashem knew that at some point in the future other people would dispute Bnei Yisrael's claim to these lands and therefore He wanted a historical record of their purchase.
The Ramban however offers a different approach. In one of his explanations for the necessity of this story he writes (Breishit 23:19),

ונכתבה זאת הפרשה להודיע חסדי השם עם אברהם שהיה נשיא אלהים בארץ אשר בא לגור שם והיחיד, וכל העם היו קוראין לו "אדוני", והוא לא אמר להם כן שהיה שר וגדול, וגם בחייו קיים לו ואגדלה שמך והיה ברכה
And this section was written to inform us of the kindness of Hashem toward Avraham that he was a prince of God in the land in which he came to settle and he was unique. And the entire nation referred to him as 'My Master', and he never told them that he was an officer or great person. In his life the blessing was fulfilled that his name would become great and it would be for a blessing

According to Ramban the importance of this story is contained within the periphery. The fact that Avraham bought a burial plot for his wife is immaterial; what is important is the fact that God's blessing started to come true in Avraham's lifetime because the people honored him and treated him as God's prince.
The Chizkuni however offers a different approach, which directly contradicts the Ramban's claim. The Chizkuni notes that when Avraham initially spoke to the Bnei Cheit about purchasing a burial plot he, "rose up and bowed down" (23:7). On this the Chizkuni comments,

ויקם אברהם וישתחו אברהם היה צריך לכולן שאפי' מכר לו עפרון את השדה לא היה אברהם רשאי לעשותו בית הקברות שלא ברשות כל בני העיר ולכך הוצרך לקום כדי להשתחוות לכולם אפי' לאותם של אחוריו. אבל בהשתחות לעפרון שהיה יחידי לא הוצרך לקום אלא להשתחות לפניו.
Avraham rose up and bowed down. Avraham needed to do both of these because even if Ephron sold him the field Avraham would not have been permitted to convert it into a cemetery without the permission of all of the townspeople. Therefore he need to rise in order to bow down to all of them, even those who were behind him. But when he bowed down to Ephron, who was but one individual, he did not need to rise, rather he bowed down before him.

According to Chizkuni, even if Avraham was known as a prince, as Ramban writes, he still needed to grease the palms of the local zoning board or else he would not have been able to bury Sara where he wanted to. According to the Ramban, Avraham did not have a difficult time finding a resting place for Sara - he was a prince and the locals were honored to sell him the land. However, according to Chizkuni, Avraham did not receive any preferential treatment and needed to go through the political process just like anyone else.
The explanation of the Chizkuni fits in well with a Midrash (Midrash Ha'Gadol), which explains that the need to purchase a burial plot for Sara was yet another test of Avraham's belief and dedication to Hashem. Writes the Midrash,

בוא וראה ענוותנותו של אברהם אבינו! שהבטיחו הקב”ה לתת לו ולזרעו את הארץ עד עולם ועכשיו לא מצא קבורה אלא בדמים מרובים, ולא הרהר אחר מידותיו של הקב”ה ולא קרא תגר, ולא עוד אלא שלא דיבר עם יושבי הארץ אלא בענוה, שנאמר: “גר ותושב אנכי עמכם” - אמר לו הקב”ה: אתה השפלת עצמך, חייך שאני אשימך אדון ונשיא עליהם.
Come and see the humbleness of Avraham Avinu! God had promised to give him and his offspring the Land and now he could only find a burial place for a large sum of money and he did not question the ways of the Holy One Blessed be He and he did not rebel; not only that, but he even spoke to the locals with humility, for it says, 'I am an alien and resident among you' - The Holy One Blessed be He said to him: You lowered yourself, I swear that I will make you a master and prince over them.

According to the Midrash, this entire chapter is a test of Avraham's will. God had commanded him to leave his homeland and he listened. God had brought a famine to Canaan, forcing him to leave for Egypt and his faith never wavered. God had commanded him to sacrifice his beloved son and he was willing to go through with it. Then his wife died and he wanted to bury her in the Land that God had promised to give him, but he had to pay a large sum of money for a small piece of the Land that was supposed to be his. Avraham could have said, "Enough is enough! I was willing to sacrifice my own son, why do I deserve this?" But he did not. As the Chizkuni and the Midrash teach us, he went through with the ordeal of purchasing the plot of land just like anyone else. The Torah goes into such great detail about this business transaction to show us Avraham's humility in passing yet another test; Avraham got approval both from the local zoning board and from Hashem.

Archeological Findings and Sarah's Treatment of Hagar

After years of suffering without a child, Sarah told Avraham to marry their Egyptian maidservant Hagar. Sarah felt that the blessings that Hashem had promised to give to Avraham's offspring could not possibly be fulfilled through her because of her old age and she told Avraham to fulfill his destiny through Hagar. Shortly after marrying Avraham, Hagar conceived a child (Breishit 16:4)

ויבא אל הגר ותהר ותרא כי הרתה ותקל גברתה בעיניה
He consorted with Hagar and she conceived; and when she saw that she had conceived, her mistress was lowered in her esteem.

Sarah had hoped that Hagar and Avraham would have a child together, but she did not anticipate that this would lead Hagar to belittle her. Rashi comments,

אמרה שרי זו אין סתרה כגלויה, מראה עצמה כאלו היא צדקת ואינה צדקת, שלא זכתה להריון כל השנים הללו, ואני נתעברתי מביאה ראשונה
She said, 'This Sarai her conduct in secret is not like her conduct in public. She shows herself as if she is a righteous woman, but she is not a righteous woman, for she did not merit to conceive all these years, whereas I have conceived from the first union.'

Sarah complained to Avraham about Hagar's negative attitude and he told her that she was free to do with her whatever she saw fit. The Torah tells us (16:6)

ותעניה שרי ותברח מפניה
And Sarai dealt harshly with her, so she fled from her.

What exactly did Sarah do to Hagar that caused her to runaway? Rashi writes that she enslaved her harshly. Radak, however, goes into greater detail. He writes,

ומה שעשתה שרי לא היה טוב בעיני הא-ל, כמו שאמר המלאך אל הגר: “כי שמע ה’ אל עניך” והשיב לה ברכה תחת ענויה.
And what Sarai did was not proper in the eyes of God, as the angel said to Hagar: 'for Hashem has heard your suffering' and he gave her a blessing because she had suffered.

Radak claims that Sarah sinned by treating Hagar harshly. He goes on to describe exactly what Sarah did to Hagar,

עשתה עמה יותר מדאי, ועבדה בה בפרך. ואפשר שהייתה מכה אותה ומקללת אותה, ולא הייתה יכולה לסבול וברחה מפניה... אף על פי שאברהם מחל לה על כבודו...היה ראוי לה למשוך את ידה לכבודו ולא לענותה... אין ראוי לאדם לעשות כל יכולתו במה שתחת ידו
She did too much to her and she enslaved her with hard labor. And it is possible that she beat her and cursed her, and she could not withstand it so she fled...even though Avraham gave up his honor...it would have been appropriate for her to hold back for his honor and not afflict her...It is not appropriate for a person to do all that is within their power to a subordinate.

Radak is not alone in his criticism of Sarah. The Ramban criticizes both Avraham and Sarah when he writes,

חטאה אמנו בעינוי הזה, וגם אברהם בהניחו לעשות כן
Our mother committed a great sin with her harsh treatment and Avraham also sinned by allowing her to do this

Rabbi Elchanan Samet (Iyunim L'Parashot HaShavua Vol 1 pp. 33) writes that there is evidence, found in archeological digs that might defend Sarah from her critics. He quotes a Hebrew translation of Hammurabi's Code, the system of laws developed by King Hammurabi who lived during the same time period as Avraham, Yitzchak and Yaakov. Hammurabi's code records the following law,

כי ייקח אישה כוהנת, והיא תיתן לאישה אמה, אם תלד בנים ואחרי כן תשווה עצמה לגברתה, גברתה לא תיתן אותה בכסף, מפני שילדה בנים. היא תשים עליה אות ותמנה אותה בין האמהות. אם לא תלד בנים, תיתן אותה בכסף
When a man marries a woman who is barren and she gives her husband a maidservant, if the maidservant has children and then puts herself on the same level as her mistress, her mistress may not sell her, for she has had children. She shall place a symbol on her and enumerate her amongst the maidservants. If she does not have children she may be sold.

In the time and place of Avraham it was common practice for a barren woman to give over her maidservant to her husband in order for them to have children. However, the maidservant remained a maidservant; she was not on equal footing with her mistress. Hagar viewed herself as being superior to Sarah because she conceived the first time she was with Avraham and she began to act like she was the head of the household. Sarah complained to Avraham and he told her that she was free to do what she wished, because Hagar had acted inappropriately - what she did was against the law. Hammurabi's code called for the mistress to "place a symbol on her", to do something to let the maidservant know her place in the household hierarchy. Accordingly, Sarah and Avraham did not sin when they afflicted her, it was Hagar who sinned by viewing herself as an equal.
Given this archeological evidence, one could argue that Radak and Ramban would take back what they said about Sarah's behavior. On the other hand, perhaps they would stand their ground; such behavior may have been permissible according to the letter of the law, according to Hammurabi's code, but perhaps Avraham and Sarah were expected to not simply abide by the letter of the law, but rather to go beyond it.

Escaping the Famine: Did Avraham Sin?

Not long after he arrived in Canaan, Avraham was forced to make a critical decision. He had uprooted his entire family from Charan and moved to Canaan because Hashem had commanded him to do so, but a famine had struck his new homeland (Breishit 12:10). Without the food and water he and his family needed to survive, what was Avraham to do? The Ramban (12:10) writes,

יציאתו מן הארץ, שנצטווה עליה בתחילה, מפני הרעב, עון אשר חטא, כי האלהים ברעב יפדנו ממות. ועל המעשה הזה נגזר על זרעו הגלות בארץ מצרים ביד פרעה
His leaving the Land, about which he was commanded to settle because of the famine, was a sin, for God, in times of famine, saves people from death. And because of this, the exile in Egypt was decreed on his offspring

According to Ramban, Avraham should have had faith in Hashem that He would provide for him during the tough times of the famine; just like Avraham had faith in Hashem that things would work out if he moved from Charan to Canaan, so too he should have had faith and remained in Canaan. His sin was so egregious that Hashem decreed that Avraham's children would suffer as a result and be exiled to the very Egypt that Avraham had runaway to.
Rabbi Don Isaac Abrabanel, vehemently disagrees with the Ramban's theory. He writes,

וכבר ראית דברי הרמב"ן...וכבר תפשו על הדעת הזה הר"ן כי הנה יציאתו מארץ כנען לארץ מצרים מפני הרעב חז"ל מנוהו מכלל הנסיונות ובידוע שה' צדיק יבחן ומי שיעמוד בנסיונו אין ראוי שיקרא חוטא וחליל שינסה השם את אברהם להכשילו...ודי שנאמר עתה ששתי הסבות הניעו לאברהם לרדת למצרים. האחת היא שחשב שהמצוה האלהית היתה לשבת בארץ כנען ושלא נאסר עליו מפני זה ללכת מצרים אם לסחורה או לצורך אחר כי לא היה עובר בזה על המצוה כיון שלא היה דעתו בהליכתו להתישב שמה דירת קבע אלא דירת עראי וימים אחדים עד עבור הרעב ומיד ישוב לארץ כנען וכמו שהיו עושים בני ישראל בהיותם בארץ שהיו הולכים למצרים לעשות סחורה ושבים ובזה האופן היו מעשיו של אברהם לשם שמים... וכבר זכרה התורה הסבה הזאת באמרה וירד אברם מצרים לגור שם כי היה הרעב בארץ רוצה לומר בדרך גרות לא להתישב שם. והסבה הב' היא שהמצוות האלהיות הם על תנאי אשר יעשה אותם האדם וחי בהם ולא שימות בהם
And I have already seen the words of the Ramban...Rabbeinu Nissim has already challenged this position because Avraham left the Land of Canaan for Egypt because of the famine. Furthermore our sages enumerated this as one of the tests given to Avraham and it is known that Hashem only tests the righteous and those who can stand up to his tests. It is suitable to explain that Avraham had two motives for going down to Egypt. Firstly he believed that the divine commandment was to settle in the Land of Canaan; travel to foreign countries such as Egypt for business or some other need was not forbidden. He did not violate the commandment because he did not travel there to settle, but rather he went there temporarily until the famine ended - and when it did, he immediately returned. This is what Bnei Yisrael did when they eventually settled the Land - they went to Egypt to conduct business and then returned home. In a similar vein, Avraham's actions were for the sake of Heaven. And the Torah already alludes to this fact when it says, 'Avraham went down to Egypt to dwell their because there was a famine in the land.' This means to say, he went as a stranger, not to settle. And the second reason he went to Egypt is because God's commandments are conditional - one does not need to give up their life in order to fulfill them.

Rabbi Abrabanel argues with the Ramban and claims that Avraham's actions could not have been a sin because if his acts were sinful, he would have failed one of the tests given to him by God. Furthermore, there was no sin in going to Egypt temporarily. Finally, he went to Egypt because had he stayed in Canaan he would have had to do so at the risk of his life and the lives of his family members. Hashem had commanded him to settle and live in Canaan, not to die there of starvation.

Rambam's History of Religion

The Rambam, in the first chapter of his Hilchot Avodat Kochavim, gives a brief history of religious practice beginning with the creation of the world through the birth of the Jewish people. The Rambam writes that at first man exclusively worshiped God. However during the days of Enosh (Breisht 5:6,9-11) the generation's belief system was corrupted by a mistaken theory. The people reasoned that God had placed the sun, the moon, stars and planets in the heavens because He held them in high regard. The people then reasoned further, that it would be appropriate to worship and praise the stars as a way of honoring Hashem; everyone knew that Hashem was the only God, however they felt that a king is honored when his most loyal servants are honored.
As the years went by false prophets emerged claiming that they were told by God to build temples and offer sacrifices to the sun, moon and stars. They also claimed to have been told to build images and idols of the constellations. As time went on, people began to claim that the idols and the sun and the moon and the stars were actual gods; no longer were they "servants of God", they themselves were gods. As time went on even further, the people forgot the One and true God entirely.
Rambam points out that along the way there were individuals who were able to recognize the existence of God, such as Noach, Shem, Eiver and Metushelach. However, no one was able to reach the heights that Avraham reached. Avraham, writes the Rambam, spent day and night contemplating the existence of a single God. He looked at the sun, moon and stars and believed that there must be a deity controlling them; they could not be without a leader. Finally, at the age of 40, Avraham came to the realization that there was only one God in the world. Shortly thereafter he began to spread the word of God to people of his town. He would engage in religious debates with them and would always emerge victorious. Avraham's attempts to convert people to monotheism caused him to be ridiculed by his fellow townspeople, eventually leading the king to throw him into a fiery furnace, prompting his family's move from Ur Kasdim to Charan.
Avraham successfully spread monotheism wherever he went and eventually passed on his position as God's chief advocate to his son Yitzchak who then passed it on to Yaakov. And the rest is history.

Comparing Avraham and Noach

Given their close proximity to one another in the Torah and their loyalty to Hashem, it is understandable that Chazal, through Midrashim, compare Noach and Avraham to one another. The most well known comparison is mentioned by Rashi in the beginning of Parshat Noach (Breishit 6:9). The Torah writes that Noach was a tzaddik, a righteous man, in his generation. Picking up on the words "in his generation," Rashi cites a debate that is found in the Midrash:

יש מרבותינו דורשים אותו לשבח, כל שכן שאלו היה בדור צדיקים היה צדיק יותר, ויש שדורשים אותו לגנאי, לפי דורו היה צדיק, ואלו היה בדורו של אברהם לא היה נחשב לכלום
Some of the sages interpret it (the phrase 'in his generation'), favorably: How much more so if he had lived in a generation of righteous people, he would have been even more righteous. Others interpret it derogatorily: In comparison with his generation he was righteous, but if he had been in Abraham’s generation, he would not have been considered of any importance.

Those who viewed Noach as a tzaddik who would have transcended generations believed that had he lived during a time period other than that of the evil generation of the Flood, he would have flourished even more. On the other hand, those who claim that Noach "would not have been considered of any importance" in Avraham's generation believe that Noach's righteousness was relative; he was righteous, but look at the people around him - had he lived at a time when the rest of humanity possessed the least bit of morality and integrity he would not have stood out like he did in his generation.
While the debate over the transcendence of Noach's righteousness is left unresolved, the Zohar cites another difference between Noach and Avraham, which seems to indicate that Noach's righteousness was relative. The Zohar writes,

“

ויגש אברהם ויאמר: האף תפסה צדיק עם רשע” (בראשית יח,כג) - אמר ר’ יהודה: מאן חמא אבא דרחמנותא כאברהם? תא חזי: בנח כתיב (ו,יג-יד): “ויאמר אלוקים לנח: קץ כל בשר בא לפני... והנני משחיתם את הארץ. עשה לך תבת עצי גפר...” ואשתיק ולא אמר לו מידי ולא בעי רחמי. אבל אברהם, בשעתא דאמר ליה קב”ה: “זעקת סדום ועמורה כי רבה וחטאתם כי כבדה מאד. ארדה נא ואראה...” - מיד כתיב: ויגש אברהם ויאמר: האף תפסה צדיק עם רשע
'And Abraham drew near and said, will You also destroy the righteous with the wicked? (Breishit 18:23) - said Rabbi Yehuda: Who has seen a father as compassionate as Avraham? Come and see: Regarding Noach it is stated (6:13) 'and God said to Noach, the end of all flesh is come before me;...and behold I will destroy them from the earth. Make an ark of gopher wood...' And Noach held his peace and said nothing, neither did he intercede. Whereas Avraham, as soon as the Holy One blessed be He said to him: 'Because the cry of Sodom and Gomorrah is great, and because their sin is very grievous. I will go down and see...' Immediately, as it is stated, 'And Abraham drew near and said: Will you destroy the righteous with the wicked?'

When Hashem told Noach that He was going to destroy the world and that he should build an ark to save himself and his family, Noach obediently listened. He was a tzaddik and was worthy of being saved. However, according to the Zohar, Avraham was greater because when informed that Sodom was going to be destroyed he challenged Hashem in the hopes that he would be able to save the residents of Sodom and Gomorrah.
In the words of Nechama Leibowitz (Iyunim L'Sefer Breishit pp. 46),

נח אינו ערב לאנושות, נח אין בו אחריות לעולם כולו, נח הוא מאלה הניצולים אשר את נפשם הצילו. והעולם - יחרב. והוא נחרב. “צדיק תמים?” כן, בדורותיו.
Noach a guarantor of mankind, Noach does not have a responsibility to the world as a whole. Noach belonged to those who were satisfied to save their own souls, while the world is destroyed. [He was] 'a perfect tzaddik?' Yes, but only in his generation.