Answer:
This is a tricky verse until you understand what exactly it was saying.
Genesis 6:3 And the LORD said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years.
This was a time before the flood when wickedness was widespread, so much so that only Noah and his family found grace in God’s sight. When God spoke this prophetic verse, it literally meant “in 120 years I am sending the flood to destroy all this wickedness!” It happened just as God said it would, 120 years later.
It shows how angry God was over the sin, yet it also demonstrates His great mercy in that He was still willing to allow another 120 years for anyone to repent. 1 Peter 3:20 Which sometime were disobedient, when once the longsuffering of God waited in the days of Noah, while the ark was a preparing, wherein few, that is, eight souls were saved by water.
The part about ” My spirit shall not always strive with man” demonstrates that we come to repentance only by the Holy Spirit working on our hearts to bring an awareness of God to us, yet the ultimate choice is ours. In the case of Genesis 6:3, only 8 people listened and headed to the Spirit during that 120 year span where God’s Spirit continued to strive and tug at man’s heart right up until the time of the first great raindrop that started the flood.
Pastor Brad