In 2019, the United Nations reported that “all societies in the world are in the midst of [a] longevity revolution—some are at its early stages and some are more advanced.” Although it is highly improbable that nations will ever succeed in prolonging the average lifespan to any significant extent, there was a time when mankind lived extraordinarily long lives during the time leading up to the flood. Scripture teaches that there was then a progressive shortening of man’s lifespan from Noah to Abraham, and from Abraham to Moses. There are several important reasons why God purposed to allow the first generations of humanity to live as long as they did; and, there is a significant theological rationale for why He shortened the lifespan of humanity.
At the beginning of Genesis, we read of a number of extraordinarily long lives at the beginning of human history. In Genesis we read that Adam lived 930 years, Seth lived 912 years, Enosh lived 905 years, Kenan lived 910 years, Mahalalel lived 895 years, Jared lived 962 years, Methuselah lived 969 years, Lamech lived 777 years, and Noah lived 950 years (Gen. 5:5, 8, 11, 14, 17, 20, 27, 31; 9:29).
In the first place, extended lifespans allowed mankind to populate the earth in partial fulfillment of the promise of redemption (Gen. 3:15). God had promised to redeem a people through the seed of the woman. God chose to use the very people who brought sin and misery into the world to populate the world in light of His promise of redemption. In Genesis 5:4 we read, “The days of Adam after he fathered Seth were 800 years; and he had other sons and daughters.” We don’t know how many children Adam and Eve had in addition to the three sons we read of in the early chapters of Genesis. However, we do know that they had many other children, which would certainly include daughters, who must have married each other and then produced children themselves. The mandate to be “fruitful and multiply” (Gen. 1:28) did not pass away after the fall. God still intended for humanity to populate and fill the earth. Martin Luther explained:
If you carefully compute the years of Adam, our first parent, you will observe that he lived more than fifty years together with Lamech, Noah’s father. Therefore, Adam saw all his descendants down to the ninth generation, and he had an almost countless multitude of sons and daughters whom Moses does not enumerate, since he was content to enumerate the main line of descent and its closest branches down to Noah.
In light of the fall, it was a great kindness from God to Adam to allow him to see so many of his descendants—even to the seventh generation. This is heightened by the fact that Adam’s first son murdered his second son. How kind our God was to show Adam something of His covenant faithfulness by allowing him to participate in and witness the populating of the earth. What a reminder to mankind that God had promised to send a Redeemer into the world—the “offspring” of the woman.
In addition to the mandate to be “fruitful and multiply” (Gen. 1:28), the mandate to cultivate the earth and develop civilizations was still in force. Perhaps another reason why God granted extended lifespans in the primitive era of human history was to give people the time to contribute to the initial development of society. How much quicker would cultures emerge and exploratory advancement occur if man lived longer in the primitive era? Although Scripture focuses on Cain and his descendants as those who made social advances for themselves and their evil intentions (Gen. 4:17–24), it is reasonable to conclude that the godly lineage of Seth also made contributions to society for the glory of God. By prolonging their lives, the Lord allowed image bearers to do significant exploration, invent, and make progress for the good of human society by means of longer lifespans.