Tertullian - On Monogamy

As for what pertains to antiquity, what more ancient formal type can be brought forward, than the very original fount of the human race? One female did God fashion for the male, culling one rib of his, and (of course) (one) out of a plurality. But, moreover, in the introductory speech which preceded the work itself, He said, “It is not good for the man that he be alone; let us make a help-meet for him.” For He would have said “helpers” if He had destined him to have more wives (than one). He added, too, a law concerning the future; if, that is, (the words) “And two shall be (made) into one flesh”—not three, nor more; else they would be no more “two” if (there were) more—were prophetically uttered. The law stood (firm). In short, the unity of marriage lasted to the very end in the case of the authors of our race; not because there were no other women, but because the reason why there were none was that the first-fruits of the race might not be contaminated by a double marriage. Otherwise, had God (so) willed, there could withal have been (others); at all events, he might have taken from the abundance of his own daughters—having no less an Eve (taken) out of his own bones and flesh—if piety had allowed it to be done. But where the first crime (is found) homicide, inaugurated in fratricide—no crime was so worthy of the second place as a double marriage. For it makes no difference whether a man have had two wives singly, or whether individuals (taken) at the same time have made two. The number of (the individuals) conjoined and separate is the same. Still, God’s institution, after once for all suffering violence through Lamech, remained firm to the very end of that race. Second Lamech there arose none, in the way of being husband to two wives. What Scripture does not note, it denies. Other iniquities provoke the deluge: (iniquities) once for all avenged, whatever was their nature; not, however, “seventy-seven times,” which (is the vengeance which) double marriages have deserved.