Genesis 6:3

This comes in here as a token of God's displeasure at those who married strange wives; he threatens to withdraw from them his Spirit, whom they had grieved by such marriages, contrary to their convictions: fleshly lusts are often punished with spiritual judgments, the sorest of all judgments. Or as another occasion of the great wickedness of the old world; the Spirit of the Lord, being provoked by their resistance of his motions, ceased to strive with them, and then all religion was soon lost among them. This he warns them of before, that they might not further vex his Holy Spirit, but by their prayers might stay him with them. Observe in this verse, I. God's resolution not always to strive with man by his Spirit. The Spirit then strove by Noah's preaching (Pe1 3:19, Pe1 3:20) and by inward checks, but it was in vain with the most of men; therefore, says God, He shall not always strive. Note, 1. The blessed Spirit strives with sinners, by the convictions and admonitions of conscience, to turn them from sin to God. 2. If the Spirit be resisted, quenched, and striven against, though he strive long, he will not strive always, Hos 4:17. 3. Those are ripening apace for ruin whom the Spirit of grace has left off striving with. II. The reason of this resolution: For that he also is flesh, that is, incurably corrupt, and carnal, and sensual, so that it is labour lost to strive with him. Can the Ethiopian change his skin? He also, that is, All, one as well as another, they have all sunk into the mire of flesh. Note, 1. It is the corrupt nature, and the inclination of the soul towards the flesh, that oppose the Spirit's strivings and render them ineffectual. 2. When a sinner has long adhered to that interest, and sided with the flesh against the Spirit, the Spirit justly withdraw…

6:3 will not put up with: Many think that this is an announcement of God’s decision to withdraw the restraining influence of his Spirit from human society and allow human wickedness to run its full course. Others think it means that God would withdraw his life-giving breath from humans at an earlier age (ruakh, the Hebrew term for “spirit,” can also mean “breath”; see 6:17; 7:22; see also Ps 104:29-30). • normal lifespan will be no more than 120 years (literally his days will be 120 years): It is possible that this was a new restriction on the number of years individuals would generally be allowed to live (so the NLT). However, for generations after the flood, humans lived well beyond 120 years (see, e.g., Gen 11:10-26). An alternative interpretation sees this as a 120-year grace period before the arrival of the flood (see Jon 3:4; Matt 24:37-38; 1 Pet 3:20; 2 Pet 2:5).