Musar על עירובין 36:24

Noach then was righteous in terms of his generation since he responded to inspiration from "above." G–d "encouraged" Noach during the one hundred and twenty years prior to the deluge. He sent him on a mission to warn his contemporaries to repent of their wicked ways. The Torah however, records only מקצת שבחו בפניו, וכלו שלא בפניו. The usual meaning of this concept is that one does not reveal all of a person's merits while he is alive, whereas when eulogizing such a person one must reveal all his merits. In this instance the meaning of שלא בפינו is that Noach did not initiate his role as the conscience of mankind, but he was prompted to do so by G–d.

Every man can learn from David in the matter of repentance. And so do we find with Adam. When Adam saw that the world was punished with death because of his deed he sat fasting one hundred and thirty years, and separated himself from his wife and covered his body with garlands of figs (to remind him constantly of his sin in eating the fruit of the forbidden tree) (Erubin 18b).