“God does not make a chain of solid gold, in which the first link is a floral wreath. If the creation history is an allegory, then the narrative concerning the fall and everything further that follows can also be allegory. The writer of the Pentateuch presents his work entirely as history.”[2]
The historicity of Adam relies on the historicity of the creation account. The historicity of Abraham, Isaac, and Jacob relies on the historicity of Adam. The historicity of the Jewish nation relies on the historicity of Abraham. It is, as Vos noted, “a chain of solid gold.”
We are now left with the question concerning the rationale for the length and the shortening of the lifespan of humanity. Working back on the text from a bird’s eye view of redemptive history, several categories help us arrive at reasonable explanations. Consider the following:
Population
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 among whom marriages and procreation transpired. The mandate to be “fruitful and multiply” 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.”[3]
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 was our God 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.”
Cultivation
In addition to the mandate to be “fruitful and multiply,” the mandate to cultivate the earth and develop civilizations was still in force. God granted extended lifespans in the primitive era of human history, in order 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 lives 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 make significant exploration, invention, and progress for the good of human society by means of longer lifespans.
