Q. I been studying the Bible and have two questions. First of all how long a man can physically live. In Genesis 6:3 the Lord said, “My Spirit will not contend with man forever, for he is mortal; his days will be a hundred and twenty years.” Is that where God set a specific time frame for man?
My second question is, is time in the old testament portrayed the same way as it is now? Ex. Adam lived 930 years, Seth lived 913 years, and so forth, and so the “decline” of mans life span began. But the Bible also says this, in 2nd peter 3:8 “But do not forget this one thing, dear friends: With the Lord a day is like a thousand years, and a thousand years are like a day.” Now I know that that is taken out of context but do you believe that when God speaks of say 913 years for Seth it was a different measurement of time?
A. There was one event in the distant past that changed the length of a year from 360 days to 365.25 days. Other than that, there’s no reason to doubt the constant nature of time during man’s presence on Earth. The reference to 120 years in Genesis 6:3 doesn’t pertain to man’s natural life span, but to the length of time from God’s warning of coming judgment until the flood actually came. We know this because the human life span was much longer both before the flood and afterward. Also the context of the surrounding passage is His contention with man’s rebellion, not his life span.
The long life spans before the flood have been attributed to a water vapor canopy that surrounded the Earth and prevented the breakdown of man’s cellular regeneration process (Genesis 1:6-7). This canopy collapsed upon the Earth at the time of the flood. After the flood man’s life span began decreasing rapidly. For example Noah’s son Shem, who was already 99 when the flood came, out lived eight of the first nine post flood generations.