Question One: On the Conjugal Debt

S. Th., Suppl., q. 41, a. 3-4; II-II, q. 153, a. 2; c. Gent., III, 122 and 126.

937. The conjugal debt (le devoir conjugal; de huwelijksplicht) is the proper act of conjugal life, namely, carnal copula of itself apt for generation, to which spouses have a right and which they must mutually render to one another, since in this essentially consists the undivided custom of conjugal life. Hence it constitutes the primary office between them, just as the primary end of matrimony is the procreation of offspring, and therefore by the Apostle it is called, as it were by excellence, the conjugal debt: Let the husband render the debt to the wife; and likewise also the wife to the husband (I Cor. VII, 3). Therefore in this spouses are equal by right; hence can. 1111: "to each spouse from the very beginning of matrimony there belongs an equal right and office in regard to the acts proper to conjugal life."

Therefore the conjugal act, per se apt for the generation of offspring, not only is licit if it is done for the due end and with the due circumstances, as was proved above (n. 763), but then it is also an act of the very virtue of chastity, such as befits the conjugal state; and therefore, given the required conditions, it is also meritorious.

Hence S. Thomas, II-II, q. 153, a. 2:

"Sin in human acts is that which is contrary to the order of reason; but the order of reason has this, that it order each thing suitably to its end; and therefore it is not a sin if through reason a man uses certain things for the end for which they are, in a suitable mode and order, provided that end is something truly good. But just as it is a good that the bodily nature of one individual be preserved, so also it is a certain excellent good that the nature of the human species be preserved. But just as the use of foods is ordered to the preservation of the life of one man, so also the use of venereal things is ordered to the preservation of the whole human race; whence Augustine says: What food is to the safety of a man, this intercourse is to the safety of the race. And therefore, just as the use of foods can be without every sin, if it is done in the due mode and order according as it befits the safety of the body, so also the use of venereal things can be without every sin, if it is done in the due mode and order, according as it is fitting for the end of human generation."

We shall speak:

1° of the liceity of conjugal copula,

2° of the circumstances of conjugal copula,

3° of acts connected with conjugal copula,

4° of excess in the use of marriage,

5° of defect in the use of marriage.