And the days of Adam, after he had begotten Seth, were eight hundred years,.... The Septuagint version is seven hundred; for having added one hundred years more the should be, to the years of his life before the birth of Seth, here they are taken away to make the number of his years complete:

and he begat sons and daughters; not only after the birth of Seth, but before, though we have no account of any, unless of Cain's wife; but what their number was is not certain, either before or after; some say he had thirty children, besides Cain, Abel, and Seth; and others a hundred (c). Josephus says the number of children, according to the old tradition, was thirty three sons and twenty three daughters. (d)(These families had at least five children, for one son is named as well as other sons and daughters. Therefore there must be at least three sons and two daughters in each family. For a family to have at least three sons and two daughters, according to the laws of chance, a family must on the average have nine children for this to be a near certainty. Hence the families listed in this chapter must have been large by today's standards. Given their long life, this is not at all unusual. However even today, the Old Order Mennonites of Waterloo County in Ontario and Lancaster County in Pennsylvannia, have many families this large. Ed.)

(c) Shalshalet Hakabala, fol. 74. 2.((d) Joseph. Antiqu. l. 1. c. 1. footnote on point 3.

And the days of Adam after he had begotten Seth were eight hundred years: and he begat sons and daughters:

5:1-5 Adam was made in the image of God; but when fallen he begat a son in his own image, sinful and defiled, frail, wretched, and mortal, like himself. Not only a man like himself, consisting of body and soul, but a sinner like himself. This was the reverse of that Divine likeness in which Adam was made; having lost it, he could not convey it to his seed. Adam lived, in all, 930 years; and then died, according to the sentence passed upon him, To dust thou shalt return. Though he did not die in the day he ate forbidden fruit, yet in that very day he became mortal. Then he began to die; his whole life after was but a reprieve, a forfeited, condemned life; it was a wasting, dying life. Man's life is but dying by degrees.