Jamieson, Fausset & Brown, on Gen 6:3

“And God said: My spirit shall not remain in man for ever, because he is flesh, and his days shall be a hundred and twenty years.”

“flesh--utterly, hopelessly debased. And the Lord said, My spirit shall not always strive--Christ, as God, had by His Spirit inspiring Enoch, Noah, and perhaps other prophets (Pe1 3:20; Pe2 2:5; Jde 1:14), preached repentance to the antediluvians; but they were incorrigible. yet his days shall be an hundred and twenty years--It is probable that the corruption of the world, which had now reached its height, had been long and gradually increasing, and this idea receives support from the long respite granted.”

Imported from an open dataset — not yet checked against the printed edition.