The adversaries cavil at these arguments; they say that in the beginning the commandment was given to replenish the earth but that now since the earth has been replenished, marriage is not commanded. See how wisely they judge! The nature of men is so formed by the word of God that it is fruitful not only in the beginning of the creation, but as long as this nature of our bodies will exist just as the earth becomes fruitful by the word Gen. 1, 11: Let the earth bring forth grass, yielding seed. Because of this ordinance the earth not only commenced in the beginning to bring forth plants, but the fields are clothed every year as long as this natural order will exist. Therefore, just as by human laws the nature of the earth cannot be changed, so, without a special work of God the nature of a human being can be changed neither by vows nor by human law [that a woman should not desire a man, nor a man a woman]. Secondly. And because this creation or divine ordinance in man is a natural right, jurists have accordingly said wisely and correctly that the union of male and female belongs to natural right. But since natural right is immutable, the right to contract marriage must always remain. For where nature does not change, that ordinance also with which God has endowed nature does not change, and cannot be removed by human laws. Therefore it is ridiculous for the adversaries to prate that marriage was commanded in the beginning, but is not now. This is the same as if they would say: Formerly, when men were born, they brought with them sex; now they do not. Formerly, when they were born, they brought with them natural right, now they do not. No craftsman (Faber) could produce anything more crafty than these absurdities, which were devised to elude a right of nature. Therefore let this remain in the case which both Scripture teaches and the jurist says wisely, namely, that the union of male and female belongs to natural right. Moreover, a natural right is truly a divine right, because it is an ordinance divinely impressed upon nature. But inasmuch as this right cannot be changed without an extraordinary work of God, it is necessary that the right to contract marriage remains, because the natural desire of sex for sex is an ordinance of God in nature, and for this reason is a right; otherwise, why would both sexes have been created? And we are speaking, as it has been said above, not of concupiscence, which is sin, but of that desire which they call physical love [which would have existed between man and woman even though their nature had remained pure], which concupiscence has not removed from nature, but inflames, so that now it has greater need of a remedy, and marriage is necessary not only for the sake of procreation, but also as a remedy [to guard against sins]. These things are clear, and so well established that they can in no way be overthrown.