ASV notes on Genesis 8:20-21
Noah build and alter and offered clean animals and birds to God, Noah loved God in his heart and God felt it and received the offerings and God smelled the pleasing aroma, looks like God was content and promises that He never again will curse the ground because of man. This looks promising, but then God gives the reason for not cursing the ground anymore; “for the intent of man’s heart is wicked from his youth.”
God confirmed that in man there was no hope of salvation, Noah was considered righteous, but the hope was not in him, and it had to come from heaven. You can try to do good, help others, support good works, it does not matter, your heart is wicked from your youth, and every single baby borne on earth is born wicked.