4. There is this further, that in that very debt which married persons pay one to another, even if they demand it with somewhat too great intemperance and incontinence, yet they owe faith alike one to another. Unto which faith the Apostle allows so great right, as to call it |power,| saying, |The woman hath not power of her own body, but the man; again in like manner also the man hath not power of his own body, but the woman.| But the violation of this faith is called adultery, when either by instigation of one's own lust, or by consent of lust of another, there is sexual intercourse on either side with another against the marriage compact: and thus faith is broken, which, even in things that are of the body, and mean, is a great good of the soul: and therefore it is certain that it ought to be preferred even to the health of the body, wherein even this life of ours is contained. For, although a little chaff in comparison of much gold is almost nothing; yet faith, when it is kept pure in a matter of chaff, as in gold, is not therefore less because it is kept in a lesser matter. But when faith is employed to commit sin, it were strange that we should have to call it faith; however of what kind soever it be, if also the deed be done against it, it is the worse done; save when it is on this account abandoned, that there may be a return unto true and lawful faith, that is, that sin may be amended, by correction of perverseness of the will. As if any, being unable alone to rob a man, should find a partner in his iniquity, and make an agreement with him to do it together, and to divide the spoil; and, after the crime hath been committed, should take off the whole to himself alone. That other grieves and complains that faith hath not been kept with him, but in his very complaint he ought to consider, that he himself rather ought to have kept faith with human society in a good life, and not to make unjust spoil of a man, if he feels with how great injustice it hath failed to be kept with himself in a fellowship of sin. Forsooth the former, being faithless in both instances, must assuredly be judged the more wicked. But, if he had been displeased at what they had done ill, and had been on this account unwilling to divide the spoil with his partner in crime, in order that it might be restored to the man, from whom it had been taken, not even a faithless man would call him faithless. Thus a woman, if, having broken her marriage faith, she keep faith with her adulterer, is certainly evil: but, if not even with her adulterer, worse. Further, if she repent her of her sin, and returning to marriage chastity, renounce all adulterous compacts and resolutions, I count it strange if even the adulterer himself will think her one who breaks faith.
1 Cor. vii.4 c5. Also the question is wont to be asked, when a male and female, neither the one the husband, nor the other the wife, of any other, come together, not for the begetting of children, but, by reason of incontinence, for the mere sexual intercourse, there being between them this faith, that neither he do it with any other woman, nor she with any other man, whether it is to be called marriage. And perhaps this may, not without reason, be called marriage, if it shall be the resolution of both parties until the death of one, and if the begetting of children, although they came not together for that cause, yet they shun not, so as either to be unwilling to have children born to them, or even by some evil work to use means that they be not born. But, if either both, or one, of these be wanting, I find not how we can call it marriage. For, if a man should take unto him any one for a time, until he find another worthy either of his honors or of his means, to marry as his compeer; in his soul itself he is an adulterer, and that not with her whom he is desirous of finding, but with her, with whom he so lies, as not to have with her the partnership of a husband. Whence she also herself, knowing and willing this, certainly acts unchastely in having intercourse with him, with whom she has not the compact of a wife. However, if she keep to him faith of bed, and after he shall have married, have no thought of marriage herself, and prepare to contain herself altogether from any such work, perhaps I should not dare lightly to call her an adulteress; but who shall say that she sins not, when he is aware that she has intercourse with a man, not being his wife? But further, if from that intercourse, so far as pertains to herself, she has no wish but for sons, and suffers unwilling whatever she suffers beyond the cause of begetting; there are many matrons to whom she is to be preferred; who, although they are not adulteresses, yet force their husbands, for the most part also wishing to exercise continence, to pay the due of the flesh, not through desire of children, but through glow of lust making an intemperate use of their very right; in whose marriages, however, this very thing, that they are married, is a good. For for this purpose are they married, that the lust being brought under a lawful bond, should not float at large without form and loose; having of itself weakness of flesh that cannot be curbed, but of marriage fellowship of faith that cannot be dissolved; of itself encroachment of immoderate intercourse, of marriage a way of chastely begetting. For, although it be shameful to wish to use a husband for purposes of lust, yet it is honorable to be unwilling to have intercourse save with an husband, and not to give birth to children save from a husband. There are also men incontinent to that degree, that they spare not their wives even when pregnant. Therefore whatever that is immodest, shameless, base, married persons do one with another, is the sin of the persons, not the fault of marriage.