Genesis 5:13

And Cainan lived after he begat Mahalaleel eight hundred and forty years, and begat sons and daughters:

After fathering Mahalaleel, Cainan lived 840 years more fathering sons and daughters, making his whole life 910 years as one link in the nine generations from Adam to Noah that averaged about 912 years and lived nearly a thousand years. Those are literal years of full health on vegetables, fruits and grains, with no childhood sickness, fevers, consumption or agonizing death, sustained by life-giving power transmitted from Adam and Eve who had eaten of the tree of life. His long life overlapped with seven generations living at once, so truth about God was handed down by human lips from Adam to Methuselah to Shem to Abraham and onward without books. Those centuries gave unrivaled mental strength, memory and skill to plan and execute wonderful works, yet guilt grew in proportion to ability until God destroyed that long-lived race by the Flood for despising truth and giving loose rein to iniquity. That early nobility of size, strength and intellect proves man was formed in the image of God, and its decline to about 332 years after the Flood and to seventy years and less now shows mortality increasing through flesh-eating, transgression and violation of the laws of life.

Lifespan Before the Flood

After fathering Mahalaleel, Cainan lived 840 years more begetting sons and daughters, bringing his whole life to 910 years. The verse belongs to the unbroken Genesis 5 record from Adam to Noah in which nine generations averaged 912 years and, with few exceptions, lived nearly a thousand years, between nine hundred and a thousand. Those years are literal years, not a different method of computing time, and the Hebrew record, with one or two exceptions, never states how old women were at death.

Its longevity stands at the beginning of a decline to an average of 332 years in nine generations after the Flood, tapering to between one and two hundred years at the time of the Egyptian vassalage, to seventy years in the time of Moses and David, to about thirty years in Europe and America at present and twenty years in great cities, now about thirty-five years. It belongs to more than sixteen hundred years of vegetarian living on vegetables, fruits, and grains before flesh was permitted, when lives were lived in full health with no mention of childhood sickness and death, youthful or midlife feebleness, fevers, dyspepsia, gout, consumption, local organ disease, prolonged suffering, or agonizing death, but only the measure of each life and its quiet cessation when the weary springs of life stood still. That protracted life came from the life-giving power of the tree of life transmitted from Adam and Eve to their descendants, for the tree had power to perpetuate life so that while they ate of it they could not die. Only a few generations after access was lost the race in Noah's day still retained much early vigor, proving it was created with ten times more vital force than now, since its known violations of all the laws of health and life would otherwise have extinguished it altogether.

Living nearly a thousand years proves the nobility, size, physical strength, and intellect of Adam as formed in the image of God and lord over creation and pronounced very good, and the race has fallen off in size and strength in proportion to the shortening of life. Strength was not at first overcome by corrupted appetites, passions, and violations of physical law, but later generations experienced sickness, weakness, and mortality increasingly early through continued violations of the laws of life. After Noah lived 950 years and he and his sons ate flesh for a time, decline rapidly accelerated until curse, accumulated transgression, and violation of natural law bowed the race down to a brief existence marked by disease, decrepitude, and imbecility, cutting life to contemptible brevity and filling those years with pain, with diseases seizing the infant at birth and multitudes born dead as to intellect and heart by awful and unspeakable violations of God's laws of health and life.

Witness Across Overlapping Generations

Cainan stands as one link in the long-lived line from Adam through Seth to Enoch and Noah, and his 840 years after begetting Mahalaleel show how the generations overlapped so that truth about God was passed by human lips from one to another. For hundreds of years seven generations lived at the same time, making direct handing down of all that God taught Adam possible. In that chain Adam taught Methuselah, Methuselah taught Shem, Shem taught Abraham and Isaac, and Abraham and Isaac taught Jacob, the father of the tribes of Israel. That handed-down history of Abel, Seth, Enoch and Noah was later taught to Daniel and his three companions, who cherished it so that the image of God was engraved upon the heart.

Those centuries gave unrivaled advantages for gaining religious and scientific knowledge, with great physical and mental strength. Their minds did not mature late but developed early, and those who feared God and lived in harmony with His will kept increasing in knowledge and wisdom all their lives, far beyond what men who study twenty to fifty years now attain, even with books left by earlier scholars. Without books or written records, men with strong memories grasped and kept what they heard and passed it on unimpaired, and for hundreds of years they consulted together so each could profit from the knowledge and experience of all. Adam, formed in God's image and pronounced good, lived among his descendants for hundreds of years, having learned the history of creation from the Creator and having witnessed nine centuries himself, and he taught them what he knew. That long-lived people possessed rare powers to plan and execute, including many giants of great stature and strength, renowned for wisdom and skillful in devising cunning and wonderful works.

That length of life and ability was given to serve God and make His name a praise in the earth and answer the purpose for which life was given, but they failed to do this. Their guilt in giving loose rein to iniquity was in proportion to their skill and mental ability. During that time righteous men including Seth, Enoch, Methuselah, Noah and others kept the knowledge of God and the truth continually before the world. But the people despised the truth, the imaginations of their hearts were evil and only evil continually, secret societies were formed to work in darkness to do violence, and God destroyed that long-lived race by a flood.

The ages and generations from Genesis 5:5-32 thus belong to the record of the patriarchs before Noah, whose lives, with few exceptions, approached a thousand years. After Noah's time human lifespans steadily declined and mortality increased through generations. Their strength was not immediately overcome by the effects of corrupted appetites, passions, and violations of physical law, but later generations experienced sickness, weakness, and death increasingly early. The shortening of human life is therefore linked to the gradual weakening of vital forces through continued violations of the laws of life, providing a contrast between their long lives and the sickness and mortality prevalent in the present generation.