And the Lord said by His Word, All the generations of the wicked which are to arise shall not be purged after the order of the judgments of the generation of the deluge, which shall be destroyed and exterminated from the midst of the world. Have I not imparted My Holy Spirit to them, (or, placed My Holy Spirit in them,) that they may work good works? And, behold, their works are wicked. Behold, I will give them a prolongment of a hundred and twenty years, that they may work repentance, and not perish.
God Grants 120 Years for the Flood Generation to Repent
Targum Pseudo-Jonathan on Genesis 6:3