Is not the fact that God thinks that the imagination of man's heart is bent to evil from youth onwards proof that the flood was an exaggeration and that therefore he would not bring another flood in Genesis 8:21? Or did he promise this simply on Noah's merit? What was the need for God to bring this understanding to light? Atheists, agnostics, exegetes, secular scholars correlate this passage as God's admission that the flood solved nothing, some go further and argue that God missed his point and changed his approach by not promising to bring another flood, never mind. what circumstances. future generations are just as bad or even worse. In this case, would God have acted on impulse and anger and when it calmed down, did he realize that he had not solved the problem, that this is something ingrained in human beings and that from now on the approach would have to be different? What do you think? How do you understand this text?
The Alter Rebbe explains this. He asks, why is the reason for bringing the flood, and the reason for never bringing it again the same? I.e. in both cases it is because man is evil from youth? The first time He says it, He says therefore He will destroy mankind, and the second time He says it, He says therefore He will never destroy mankind.
The answer is that intellect is lower in the soul than pleasure. The intellectual argument Hashem made was the same, but before the flood, He had lost the pleasure on His creation and therefore the argument lent towards destruction. Afterwards, Noach brought back the pleasure (as indicated by Hashem smelling the pleasant fragrance of the korban before saying it the second time) so the argument lent towards mercy.
The lesson is on how powerful pleasure is and how it modifies our thinking. Being in a good mood is a moral obligation as someone in a good mood is much more inspired to do good and make the lives of everyone around them better.