Genesis 6:6 - Ellicott's Commentary On The Whole Bible

And it repented the Lord. — If we begin with the omniscience and omnipotence of God as our postulates, everything upon earth must be predestined and immutably fore-ordained. If we start with man’s free will, everything will depend upon human choice and action. Both these sides must be true, though our mental powers are too limited to combine them. In Holy Scripture the latter view is kept more prominently in the foreground, because upon it depends human responsibility. Thus here, the overwhelming of mankind by a flood, and the subsequent abbreviation of life, is set before our eyes as painful to the Deity, and contrary to His goodwill towards men, but as necessitated by the extreme depravity of even the chosen Sethite race.