“And these are the names of the Bnai Yisrael that came to Egypt. Each man with his household came with Yaakov.” (Shemot 1:1)
The passage above is the opening of Sefer Shemot. Sefer Shemot deals with the bondage of Bnai Yisrael in Egypt and their eventual redemption. The commentaries on the Torah have various views regarding the reasons for Bnai Yisrael’s bondage. Many share the view that is was a punishment for some wrongdoing. However, they differ widely regarding the specific failing that engendered the bondage a persecution in Egypt.
Nachmanides maintains they crucial incident that led to the exile and persecution of Bnai Yisrael in Egypt occurred early in Sefer Beresheit. Avraham was confronted with a famine in the land of Canaan. In response to this famine, Avraham abandoned the land of Canaan and descended to Egypt. Nachmanides maintains that Avraham sinned in his decision to leave the land of Israel and seek refuge in Egypt. Nachmanides asserts that Avraham also committed a second sin. While in Egypt, Avraham denied that Sara was his wife. He claimed that she was his sister. Avraham engaged in this deception, in order to protect himself from the Egyptians. He feared that in order to seize Sara, the Egyptians might murder her husband, but as her brother he would be safe from harassment. According to Nachmanides, Avraham should have relied upon G-d’s providence and assumed that he would be protected.
The Talmud teaches us in Tractate Taanit that it is prohibited to rely upon miracles. Each individual is required to exercise common sense. We may not endanger ourselves needlessly with the hope of being saved by a miracle. Why, then, did Avraham sin by traveling to Egypt and claiming that Sara was his sister? Both of these decisions reflect Avraham’s determination to provide for his own safety, without relying on Divine intervention.
It seems that Hashem intended to demonstrate, through Avraham, a fundamental concept of the Torah. The Almighty is the Creator of the Universe. He is aware of all the intricate details of His creation. Furthermore, He will intervene with nature on behalf of His devoted children. Towards this end, G-d endeavored to demonstrate, through Avraham, the effects of His Providence. He made Avraham wealthy and mighty; He protected him from all harm. Because of this relationship, Avraham should have stayed in the land of Israel. He would have been protected, and unharmed by the famine. Similarly, upon entering Egypt, Avraham should have acknowledged Sara as his wife. His frank honesty in the face of danger would have been rewarded. G-d would have protected Avraham from the aggression of the Egyptians. Remaining in the land of Israel and declaring Sara as his wife would have served as a demonstration G-d’s Providence, in the most dangerous of situations, over his beloved.
In short, it is prohibited for a person to rely upon a miracle. However, Avraham had a unique mission. The Almighty wished to demonstrate His Providence through Avraham. Because Avraham abandoned the land of Israel and protected Sara though deceit, he denied Hashem the opportunity to demonstrate His influence over nature on behalf of Avraham.
Nachmanides then demonstrates a remarkable set of parallels between Avraham’s experiences in Egypt and those of his descendants.
Avraham was confronted with a famine. He descended to Egypt to survive. Bnai Yisrael was confronted with famine and descended to Egypt to survive.
The Egyptians took Avraham’s wife – Sara. The Egyptians attempted to kill all the male children Of Bnai Yisrael but wanted to take the women of Bnai Yisrael for themselves.
Hashem intervened to save Avraham. He punished the Egyptians. Hashem intervened to save Bnai Yisrael and punished the Egyptians.
Finally, the Egyptians send Avraham away and he left with great wealth. The Egyptians send Bnai Yisrael away and they left with great wealth.
Nachmanides explains that this parallel occurred through design. Avraham sinned in descending to Egypt and in claiming that Sara was his sister. Instead, he should have relied on Hashem to save him from famine and danger. Nachmanides asserts that Avraham must have been guilty of wrongdoing – albeit accidental. Otherwise, he would not have experienced this misfortune. Finally, Nachmanides adds that Bnai Yisrael’s exile to Egypt was also caused by Avraham’s error.
Abravanel agrees that Nachmanides’ basic reasoning is valid. The experience in Egypt seems to be a punishment. This implies the commitment of a sin. However, he objects to ascribing this sin to Avraham. He insists that we do not have the right to ascribe a wrongdoing to Avraham that is not explicitly indicated by the Torah. Instead, he maintains that the sin was committed by the Shevatim. The brothers sinned in selling their brother Yosef into bondage. The Torah does identify their behavior as a sin.
Like Nachmanides, Abravanel offers proof to his thesis by outlining the various parallels between the sin of the Shevatim and the punishment experienced by Bnai Yisrael.
The Shevatim sold Yosef into bondage in Egypt. Their descendants experienced bondage in Egypt.
They threw Yosef into a pit. Their male descendants were thrown into the river.
The Shevatim caused Yosef to enter bondage. Yosef caused them to descend to Egypt and eventually, their descendants entered bondage.
They were caring for flocks and Yosef came to assess their work with these flocks. They descended to Egypt in order to provide their flocks with pasture.
It is interesting that although Nachmanides and Abravanel both assume that some sin led to the exile and bondage in Egypt, they differ on the specific sin. Abravanel rejects Nachmanides’ thesis because it requires that we attribute wrongdoing to Avraham by inference. He argues that although we have the authority to explain and interpret the Torah, we must work within strict perimeters. We cannot ascribe a sin to the Avot – the forefathers – that is not explicitly stated in the text of the Torah.
This is an interesting dispute. It seems that Abravanel’s criticism of Nachmanides is reasonable. Nachmanides is making remarkable and drastic inferences at the expense of Avraham! Why was Nachmanides not sensitive to Abravanel’s concerns?
Perhaps, the basis of this dispute lies in understanding these two Sages’ perspectives on the purpose and theme of the Torah’s narrative. It seems reasonable to assume that even Abravanel would agree that the Torah is not a set of biographies. There is no attempt in the Torah to provide a comprehensive biographical sketch of Avraham or any of the Avot. However, Abravanel does maintain that the Torah wishes to provide us with a characterization of Avraham and the Avot that is fundamentally complete. Our identity as Bnai Yisrael is linked and built upon the foundation of our understanding of the Avot. The image and understanding presented in the Torah of Avraham and the other Avot contains the basic information that we are to integrate into our fundamental understanding and image of these individual. Based on this understanding of the Torah, Abravanel argues that the Torah would not exclude information that is needed to understand these individuals. We cannot assume that the Torah’s characterization of Avraham is misleading or incomplete in a fundamental manner.
In contrast, Nachmanides is willing to assume that the Torah’s explicit treatment of the Avot is incomplete. This suggests that Nachmanides has a somewhat different understanding of the intent of the Torah’s narrative. It seems that according to Nachmanides, the Torah is primarily concerned with outlining the unfolding of Hashem’s providence over Bnai Yisrael. In this narrative the Avot are key characters. But they are characters in a narrative that is not primarily about them. It is about Hashem’s providence. From this perspective it possible to assume that the explicit picture that is communicated regarding the Avot may not be comprehensive. The Torah describes Avraham’s actions and decisions. It outlines the impact of these actions on the future of his descendents. This is relevant to the narrative of Hashem’s providence. However, it is not essential to this objective for the Torah to explicitly evaluate Avraham’s behavior.
 Rabbaynu Moshe ben Nachman (Ramban / Nachmanides), Commentary on Sefer Beresheit 12:10.  Mesechet Taanit 20b.