John Calvin Commentary Genesis 6:1

"And it came to pass, when men began to multiply on the face of the ground, and daughters were born unto them," — Genesis 6:1 (ASV)

And it came to pass, when men began to multiply. Moses, having enumerated in order ten patriarchs with whom the worship of God remained pure, now relates that their families also were corrupted. However, this account must be traced to an earlier period than Noah's five hundredth year.

For, to make a transition to the history of the flood, he prefaces it by declaring that the whole world was so corrupt that scarcely anything was left to God amidst the widespread falling away. So that this may be more apparent, the principle must be remembered: that the world was then, as it were, divided into two parts, because the family of Seth cherished the pure and lawful worship of God, from which the others had fallen away.

Now, although all humankind had been formed for the worship of God, and therefore sincere religion should have reigned everywhere, yet since the greater part had prostituted itself—either to an entire contempt of God or to depraved superstitions—it was fitting that the small portion which God had adopted for Himself by special privilege should remain separate from others.

It was, therefore, shameful ingratitude for the descendants of Seth to mingle with the children of Cain and with other profane peoples, because they voluntarily deprived themselves of the inestimable grace of God. For it was an intolerable profanation to pervert and confuse the order established by God.

It seems at first sight trivial that the sons of God should be so severely condemned for having chosen beautiful wives for themselves from the daughters of men.

But we must first understand:

1. It is not a minor offense to violate a distinction established by the Lord.
2. The separation of God's worshippers from profane nations was a sacred ordinance that should have been reverently observed, so that a Church of God might exist on earth.
3. The corruption was severe, since people rejected the remedy divinely prescribed for them.

In short, Moses identifies it as the most extreme disorder when the sons of the godly, whom God had separated to Himself from others as a peculiar and hidden treasure, became degenerate.

That ancient fabrication concerning the intercourse of angels with women is abundantly refuted by its own absurdity; and it is surprising that scholars should in the past have been fascinated by such crude and outlandish ravings. The opinion of the Chaldean paraphrase—namely, that it condemns promiscuous marriages between the sons of nobles and the daughters of commoners—is also unconvincing.

Moses, then, does not distinguish the sons of God from the daughters of men because they were of a different nature or of different origin, but because they were sons of God by adoption, whom He had set apart for Himself, while the rest remained in their original condition.

If anyone objects that those who had shamefully departed from the faith and the obedience God required were unworthy to be considered sons of God, the answer is straightforward: the honor is not ascribed to them but to the grace of God, which had until now been evident in their families.

For when Scripture speaks of the sons of God, it sometimes refers to eternal election, which extends only to the lawful heirs, and sometimes to external calling, according to which many wolves are in the fold. And though, in fact, they are strangers, they are still called sons until the Lord disowns them.

Indeed, even by giving them such an honorable title, Moses rebukes their ingratitude, because, by leaving their heavenly Father, they prostituted themselves as deserters.