Leviticus 20:18.

And if a man shall lie [84] The enormity of the crime is seen by the severity of the punishment; and surely, when a man and woman abandon themselves to so disgraceful an act, it is plain that there are no remains of modesty in them. God, therefore, does not only regard the offense itself, but the brutal impulse of lust, whereby men are so carried away as to degenerate from the very feelings of nature. For what wickedness would he abstain from who yields to such impurity, that he breaks through an obstacle in his fury which restrains the brutes themselves? Let us not wonder, then, that God is a severe avenger of such obscenity.

This precept [85] has no other tendency than that believers should be kept far from all filthiness, and that chastity may flourish among them. It is indeed true that a woman, under these circumstances, is withheld from connection with a man by the very foulness of the disease, whilst there is also danger of contagion; but God rather chooses here to be an instructor in decency to His people, than to perform the office of a physician. It must be remembered, therefore, that men are warned against all indelicacy, which is abhorrent to the natural sense; and, by synecdoche, married persons are exhorted to restrain themselves from all immodest lasciviousness, and that the husband should enjoy his wife's embraces with delicacy and propriety.