And the Lord smelled a sweet savour - The sacrifice offered by a righteous man like Noah in faith was acceptable as the most fragrant incense.
Lord said in his heart - same as “I have sworn that the waters of Noah should no more go over the earth” (Isa 54:9).
for - that is, “though the imagination is evil”; instead of inflicting another destructive flood, I shall spare them - to enjoy the blessings of grace, through a Savior.