Noah is recognized as a faithful and effective preacher. He stood out in his generation by being convicted by a dream. His discovery of grace is the same stuff as Abraham’s justification (for believing the promise of chiidren like the stars in the sky in number). If anything else would have turned the tide of badness pouring out of humans it was not the law or the threat of death.
And the LORD said, I will destroy man whom I have created from the face of the earth; both man, and beast, and the creeping thing, and the fowls of the air; for it repents me that I have made them. (8) But Noah found grace in the eyes of the LORD.Genesis 6:7-8