With these words Moses marked the time at which the intolerable malice of men, which earned the vengeance of the Flood, began to flourish upon the earth. At the time, he says, when the human race began to multiply — at that very time the enormous depravity of men began to flourish on earth. The human race began to multiply while Adam was still living; indeed, it is credible that within two or three hundred years from the beginning of the world it had multiplied enormously, since it is established from the sacred writings that the posterity of Jacob, in not more than three hundred years, multiplied to such an extent that at the departure of the Hebrews from Egypt six hundred thousand fighting men were counted, not including the women, the little ones, and the old (Exod. 12). Ninus, king of the Assyrians, came to his throne about two hundred and fifty years after the Flood; and in so short a span of time the human race had so propagated itself that in Ninus' army alone there were one million seven hundred thousand foot soldiers, two hundred thousand horsemen, and a little fewer than ten thousand six hundred scythed chariots, as Diodorus Siculus (book 3, chapter 2) reports from the writer Ctesias. Since, therefore, it must be believed that the fecundity of human nature was greatest at the beginning of the world, it is not to be doubted that a great multiplication of mankind likewise took place in a short time in that age.¹

FOR THIS REASON Cajetan thinks that this multiplication of men, of which Moses here speaks, took place from the time when Cain killed Abel — that is, about the one hundred and thirtieth year from the founding of the world; for it was then that Cain said, “Everyone who finds me will kill me.” But it is more probable that Moses was speaking not of just any multiplication of men, but of one exceedingly numerous and spread far and wide.²

It is therefore truer to say what Josephus relates in the first book of his Antiquities: that the notable propagation of those men before the Flood, and their decline into evil, occurred in the seventh generation after Adam. For writing of the honorable pursuits and outstanding virtues of the descendants of Seth, he added: “In this manner,” he says, “for seven generations they persevered in worshipping the one God, the Lord of all things, always keeping virtue in view. But as time went on they degenerated from their ancestral institutions, neither keeping human laws nor rendering to God his accustomed honors; and those who before had vied with one another in the exercise of virtue afterward pursued malice with twice the zeal, and so made God hostile to themselves.” Thus Josephus. Akin to this is what Theodoret relates in his 47th question on Genesis: “The descendants of Seth” (says Theodoret), “as pious and good men, were surnamed sons of God; for the race of Seth was kept separate and did not mingle with the kindred of Cain, on account of the curse laid upon him by God. But long afterward (for God brought on the Flood after more than a thousand years), seeing that the daughters of Cain's kindred were beautiful, and enticed (as is likely) by the musical instruments devised by them — for Thubal, flourishing among them, had invented the psaltery and the cithara — they mingled with them and defiled their own nobility.” Thus Theodoret. To their opinion I gladly assent.³

For it is quite probable that it was in that time of the seventh generation from Adam that this notable depravation of the human race began. For it is conjectured, from the example of Lamech, that polygamy then began to be practiced; then Henoch, who was the seventh from Adam, was translated — namely, “lest malice,” which had begun to flourish, “should change his heart, and lest deceit should beguile his soul,” as is written in the fourth chapter of the book of Wisdom. Then, through the sons of Lamech, were invented musical instruments — incitements to wantonness and luxury — and weapons — instruments for waging war and practicing cruelty.

Nor do I permit myself to pass over even those opinions which I judge false and absurd, if they have been put forward by great men or attributed to great men; for it is better that the reader be given the full store of all that is memorable, and that what we disapprove be condemned rather than passed over. The Master of the Scholastic History, in his History of the book of Genesis, chapter 31, records some opinion of Methodius which pertains to this passage of Moses. For he relates that Methodius arranged the time from the beginning of the world up to the Flood into roughly three chiliads (thousands) of years; and that in the five hundredth year of the first chiliad after the founding of the world, the sons of Cain abused the wives of their brothers in excessive fornications; that in the six hundredth year the women, turned to madness, mounted the men and thus began to abuse them; that on Adam's death Seth separated his kindred from the kindred of Cain — for Adam, while living, had forbidden their intermingling — and that Seth dwelt on Cordan, a certain mountain near Paradise, but Cain in the field where he had slain Abel (Gen. 4); that in the five hundredth year of the second chiliad men burned with lust for one another; and that in the seven hundredth year of the same chiliad the sons of Seth conceived desire [for the daughters of Cain — sentence continues on the next page].⁴

…[the sons of Seth] lusted after the daughters of Cain; and that from them the giants arose; and finally that the Flood came when the third millennium had already begun. These things the Master of the Scholastic History reports from Methodius. But these are false, and falsely fathered upon Methodius. For they rest on a manifest error of chronology, since they reckon more than two thousand years from the beginning of the world to the Flood, whereas it is established and certain that that interval was only one thousand six hundred and fifty-six years. On this matter we have argued carefully in the seventh book of the first volume of our Commentaries on Genesis, in the Disputation on the chronology of that period, through its three questions.⁵

Moreover, this is no new thing, nor to be considered here only in passing: that when men began to multiply, then they began to become worse; so that what is said in Isaiah, chapter 9, may truly be applied here: “Thou hast multiplied the nation, but hast not increased the joy.” And the multiplication of men was indeed an immense benefit of divine kindness, and a great good for human nature, such that it ought rather to have availed toward increasing piety and religion toward God than toward contempt of God, the corruption of oneself, and the violent oppression of others. Yet it was not therefore fitting that God should be more sparing in doing good, merely because men would abuse his benefits to his contempt and to their own ruin. Ambrose expressed this in few but elegant words in the book he wrote On Noah and the Ark, ch. 3. But let me finish what I began to say a little above: that in the very multiplication of men it is not virtue that is multiplied, but wickedness (flagitia). For so it indeed comes to pass that industry and frugality are generally the companions of fewness of men and of poverty, but sloth and depravity the companions of multitude and wealth. One may observe this in many cities, commonwealths, and empires once most flourishing, and indeed even in congregations of pious men prudently ordered and long renowned for the praise of holiness. For when men were few, and not equipped with great supports and ornaments of nature and fortune, it is recorded that many of them were outstanding men, both in their private pursuits and morals and in the handling of public offices and the conduct of affairs at home and in war; but, on the contrary, when men had multiplied, dominion was extended, and wealth increased both privately and publicly, then, with discipline gradually slipping, most degenerated and became daily worse, until such a pitch of wickedness was reached that the very things which had formerly been among them incitements to virtue and rewards of glorious deeds afterwards became provocations to vice and the wages of crimes. Greek and Roman history is filled with examples, but Christian history above all.⁶

But what should we suppose to be the cause of this? Is it that in human affairs too, as in natural things, virtue united is stronger than virtue divided? Now in a small number of men virtue is more united, and can be kept inviolate and free from every contagion of evil more readily than in a multitude. Or is a multitude more exposed to the contagion of external vices and evils? Or rather…⁷

Or rather because a multitude is more subject to internal dissensions and discords? For “by concord small things grow, by discord the greatest fall to ruin.” Or is it that the very fewness of men, the weakness of their resources, the slenderness of their wealth, rivalry with their betters, and fear of the more powerful restrain men from sliding into vices? Or, finally, does a burning desire to win for oneself and one’s country liberty, the greatness of dominion, and the glory of a name through good arts either extinguish or suppress all desires for baser things — not only for vices — and make men industrious, patient of toils, bold in facing dangers, and prompt and eager in undertaking and accomplishing great things? It is in this way that the blessed Augustine argues the Roman empire was enlarged, in The City of God, bk. 5, ch. 12 and following.⁸

But what does Moses mean here when he says: “When men had multiplied upon the earth, and had begotten daughters”? What does that phrase signify, “and had begotten daughters”? Were females not begotten before? Whence then did they take wives, or whence did they beget sons? For my part I think these words signify that, in that great multiplication of men, females in particular were multiplied, so that far more were then born than before. If this be referred to natural philosophy (physiologia), it is probable that it came about thus: that because of those men’s intemperance in sex and in food and drink, and because of luxury and other vices of body and mind, the generative faculty in the man being severely weakened and the vigor of the male seed impaired, a more frequent and more numerous generation of females resulted. For this reason the men of that age, enticed at once by the number and the beauty of the women, took many wives, and, having repudiated their former wives, took others and yet others according to their lust — a thing which for a long time had been unusual among the descendants of Seth. I have a twofold argument for this. For Moses above, in chapter four, writing of Lamech alone that he had two wives, indicated not obscurely that polygamy then first began. Next, we read that Noah entered the Ark with only one wife, and each of his sons with a single wife.⁹