A common question regarding the Christian worldview is the problem of our lifetimes. It doesn’t make sense that we only live a few years on earth and then spend an eternity in heaven. Why such a short physical life to determine where we spend our eternal spiritual life? To answer this question the key point to consider is that this was not God’s original design for humans. Humans (Adam and Eve) were originally created to live for an incredibly long time, some even argue that all of creation was originally designed to live infintely. However, when Adam and Eve sinned against God death entered creation. Romans 5:12; “Therefore, just as sin entered the world through one man, and death through sin, and in this way death came to all people…”
So sin enters the world, now these created beings which where designed to live longer are now cut short because of sin. Even at that, Adam is said to have lived to be to 930 years old (Gen. 5:5), and the subsequent offspring lived very long as well, with the Biblical record being Methuselah who lived to be 969 years old (Gen 5:27). In fact, all Biblical characters lived very long until after the time of Noah. After Noah, humans still lived a few hundreds years old but the age dropped significantly and within a few generations people were living very short lives like 20-30 years. Not to go too far off on a tangent, but it has all the symptoms of a genetic bottleneck that we observe in animal populations today. Bible believing biologists believe that there must have been a wide variety genes in the human gene pool which were lost when all humans were killed with only Noah and his family remaining (a genetic bottleneck). Only the genes they possessed were passed on to the repopulated humans, which unfortunately did not possess the genes to live very long.
So humans were designed to live a very long time, sin enters the world and now we’re cut down to hundreds of years, the flood creates a genetic bottle neck and life spans decrease dramatically and only in more modern times with the advancement of medicines, sanitation, nutrition, ect. do we see people living past 100 frequently. So our physical existence is now brief, but it wasn’t always that way. We were originally intended to have a very long physical life alongside with God, but our sin causes us to die and thus end that relationship with God prematurely. So God provides us with an opportunity of redemption to continue to have this eternal relationship with Him, despite death killing us physically. What we lost physically, is reconciled spiritually. Thus, we live briefly physically, but eternally spiritually.