Now there was a man of the Pharisees, named Nicodemus, a ruler of the Jews. This man came to Jesus by night and said to him, "Rabbi, we know that you are a teacher come from God; for no one can do these signs that you do, unless God is with him." Jesus answered him, "Truly, truly, I say to you, unless one is born anew, he cannot see the kingdom of God." Nicodemus said to him, "How can a man be born when he is old? Can he enter a second time into his mother's womb and be born?" Jesus answered, "Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God. That which is born of the flesh is flesh, and that which is born of the Spirit is spirit. Do not marvel that I said to you, 'You must be born anew.' The wind blows where it wills, and you hear the sound of it, but you do not know whence it comes or whither it goes; so it is with every one who is born of the Spirit." Nicodemus said to him, "How can this be?" Jesus answered him, "Are you a teacher of Israel and yet do not understand this?"
(John 3:1-10)

Can the Ethiopian change his skin
or the leopard his spots?
Then also you can do good
who are accustomed to do evil.
(Jer. 13:23)

Can a man in love with his money enter into the Kingdom of God? "It is easier for a camel to go through the eye of a needle"
(Mt. 19:24)

Can the natural man welcome the things of the Spirit of God? "They are foolishness to him and he is not able to comprehend them, because they are spiritually assessed"
(1 Cor. 2:14)

Can the human mind, as it comes into being and grows by merely natural processes, please God? "The mindset of the flesh is hostile to God; it does not submit to God's law, indeed it cannot, and those who are in the flesh cannot please God"
(Rom. 8:7-8)

Can a man enter a second time into his mother's womb and be born when he is old? Do you feel the shock of what Jesus was requiring of Nicodemus when he said, "You must be born again" (John 3:7)? It is impossible for a man to cause himself to be born again. We can't change the color of our skin. A leopard can't change his spots. A camel can't go through the eye of a needle. A natural man can't welcome spiritual things. The mindset of fallen humanity can't please God'. And old men can't be born.

None of the explanations offered in the accompanying article imply that God randomly selected the life span of early humans or that He simply reacted to natural disasters in shortening human life. Rather, Genesis 6:3 states that God acted purposefully to shorten human life spans, and Genesis 6:5 and 11 imply that the shortening of human life spans at the time of the Flood served a specific spiritual purpose.

Why did God allow for long life spans in the first place? Long life expectancies early in humanity's history reflect God's mercy and provision. Long life spans make it possible for human technology and civilization to emerge rapidly. Living 900 years gives people ample opportunity to make discoveries, develop technology, refine technological achievements, and teach all that has been learned to ensuing generations. Under these conditions, human civilization can make dramatic advances in relatively few generations.