Did Noah really preach for 120 years as some say and based on what’s written in Genesis 6:3, or did he preach for 100 years according to what I understand in Genesis 5:32 when connected with Genesis 7:6? Thanks in advance for making this topic more clear to me because when I read the passage in Genesis 6, I understand that the days of man from that point on decreased to 120 years because of the deterioration of the atmosphere after the flood.
Setting aside the question of whether Noah preached a warning about the flood at all, here’s what we can learn from the Genesis account. First of all, Genesis 5 is the listing of 10 pre-flood patriarchs from Adam to Noah. It ends with Noah’s 3 sons being born after he became 500 years old.
In Genesis 6:3 God said, “My Spirit will not contend with man forever, for he is mortal; his days will be a hundred and twenty years.”
Some claim God was shortening man’s lifespan to 120 years but there’s no historical or Biblical evidence to confirm that. (Psalm 90:10 says man’s average lifespan would be 70 years, with 80 being an exception.) The context of Genesis 6 is judgment so it’s much more likely that God was giving mankind 120 years before destroying them. Finally, Genesis 7:6 shows the flood beginning when Noah was 600 years old.
Therefore, sometime between his 500th and 600th birthdays, God informed Noah He was going to destroy mankind with a flood and told him to build an ark so he and his family would be preserved through it. If his sons were old enough to be married when God called Noah to build the ark, as Genesis 6:18 indicates, then Noah couldn’t have spent anywhere near 100 years preaching about the coming judgment. Neither one of the traditional time frames is correct.