Avot 5:2 reports that each of the ten generations after Adam angered Hashem immensely, but with great patience Hashem waited until Noach to bring the Flood. The following ten generations were equally evil, and when Hashem's patience again expired "Avraham received the reward of all of them:". Avraham proved his merit by withstanding ten trials
I'll focus on three questions, two fundamental and one ancillary, arising from these mishnayot.
1) Why didn't Noach, like Avraham, receive the reward of his predecessors?
2) What reward did those predecessors deserve, if their evil was so great? Why weren't they rewarded themeslves for their own good deeds?
3) How did the trials demonstrate the characteristics for which Avraham earned their reward?
Rabbeinu Yonah offers a fascinating but enigmatic solution to the second question, saying that Avraham received the reward of his predecessors "had they done teshuvah". This clearly explains why they did not receive the reward themselves, and why the reward was considerable. But why should Avraham be rewarded for the hypothetical deeds of others?
The answer lies in the general capacity of teshuvah to retroactively transform transgressions into mitzvot. A thumbnail explanation is that all past actions contribute essentially to the formation of the present individual - if the present personality is worthwhile, its past is legitimated. In some sense Avraham must have been the teshuvah for the ten generations before him, which means that in some sense his greatness stemmed from a transformation, rather than a rejection, of their negative drives. Noach, by contrast, had no relationship with his society. Noach separated kodesh and chol, while Avraham transformed chol into kodesh.
The sins of Noach's time were robbery/disorder and unbridled sexuality - nowhere in Noach's life do we find these drives used positively. Indeed, his major failure is at least somewaht sexual. The sins of Avraham's time are traditionally viewed as encapsulated in his famous self-justification in Phillistia "there is no fear of Elokim in this place". This is confirmed by the climactic note of the Akeidah, "now I know that you fear Elokim". But how exactly did the Akeidah manifest Avraham's redemption of his culture? ]
A possible answer emerges from recognition that the absence of fear of Elokim did not lead to spiritual vacuum, but rather to fanatic idolatry. In Avraham's culture willingness to sacrifice children for religious purposes was standard. The Akeidah was his redemption of that blind adoration by making Hashem its object.
But do we really wish Avraham's worship of Hashem to be substantively identical to the idolatry of his contemporaries?
On the textual level, this approach does not account for the continuation of Avraham's accusation - "there is no fear of Elokim in this place, and they will kill me in the matter of my wife". The sin seems to be not the generic absence of fear of Elokim, but rather the particular kind of spirituality that led to murder for the sake of one's own purity, a willingness to kill to avoid committing adultery.
But if that was the sin, the akeidah seems less a transformation than a reenactment. Was not Yitzchak (almost) sacrificed so that Avraham could fulfill his (perceived) religious duty?
The Kotzker Rebbe suggests that this is a terrible misreading of the akeidah. He begins by conceding that Avraham's willingness to sacrifice Yitzchak was contextually ordinary, that it was normal in his culture. Indeed he notes a midrash, cited by Rashi, which portrays Avraham as eager to sacrifice Yitzchak. That midrash explains the apparent redundancy in the restraining angel's cry "Do not send your hand toward the child, and do him no harm" by positing that Avraham wished to wound Yitzchak when the option of a complete sacrifice was removed. What then was the test?
The Kotzker explains that generating religious passion is easier than controlling it. We are never more dangerous than when we feel ourselves righteous, when all our lusts and bloodlusts are unleashed for what we perceive as Divine purposes. The test was not Avraham's willingness to raise the knife, but his capacity to lower it. And the midrash notes that even Avraham could do so only hesitantly.
In this view, Avraham redeemed his peers' religious passion by adapting it to a religion which never lost sight of the value of other people, which could generate the same intensity in its followers without blinding them to all other values..
Tranforming chol into kodesh is harder than separating the two, and frequently more dangerous. A culturally divorced Avraham might never have risked Yitzchak's life. But Noach's path is at best one of personal salvation; Avraham's path is the path of redemption.