And the LORD said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be a hundred and twenty years.
All Commentaries on Genesis 6:3 Go To Genesis 6
Furthermore, lest [God] may seem to be cruel in that he had not given to sinners a place for repentance, he added, “But their days will be years,” that is, they will have years to do repentance. It is not therefore that human life was contracted to years, as many wrongly assert, but that years were given to that generation for repentance, since indeed we find that after the flood Abraham lived years and others more than and years. Since indeed they despised to do repentance, God was unwilling for his decree to await its time, but cutting off the space of twenty years he brought on the flood in the one hundredth year that had been destined for doing repentance.