Reply Obj. 5: The terms "buying" and "selling" cover all kinds of non-gratuitous contracts. Wherefore it is impossible for the exchange or agency of prebends or ecclesiastical benefices to be made by authority of the parties concerned without danger of committing simony, as laid down by law [*Cap. Quaesitum, de rerum Permutat.; cap. Super, de Transact.]. Nevertheless the superior, in virtue of his office, can cause these exchanges to be made for useful or necessary reasons.
Reply Obj. 6: Even as the soul lives by itself, while the body lives through being united to the soul; so, too, certain things are spiritual by themselves, such as the sacraments and the like, while others are called spiritual, through adhering to those others. Hence (I, qu. iii, cap. Siquis objecerit) it is stated that "spiritual things do not progress without corporal things, even as the soul has no bodily life without the body."
Reply Obj. 7: The Pope can be guilty of the vice of simony, like any other man, since the higher a man's position the more grievous is his sin. For although the possessions of the Church belong to him as dispenser in chief, they are not his as master and owner. Therefore, were he to accept money from the income of any church in exchange for a spiritual thing, he would not escape being guilty of the vice of simony. In like manner he might commit simony by accepting from a layman moneys not belonging to the goods of the Church. _______________________
SECOND ARTICLE [II-II, Q. 100, Art. 2]
Whether It Is Always Unlawful to Give Money for the Sacraments?
Objection 1: It would seem that it is not always unlawful to give money for the sacraments. Baptism is the door of the sacraments, as we shall state in the Third Part (Q. 68, A. 6; Q. 73, A. 3). But seemingly it is lawful in certain cases to give money for Baptism, for instance if a priest were unwilling to baptize a dying child without being paid. Therefore it is not always unlawful to buy or sell the sacraments.
Obj. 2: Further, the greatest of the sacraments is the Eucharist, which is consecrated in the Mass. But some priests receive a prebend or money for singing masses. Much more therefore is it lawful to buy or sell the other sacraments.
Obj. 3: Further, the sacrament of Penance is a necessary sacrament consisting chiefly in the absolution. But some persons demand money when absolving from excommunication. Therefore it is not always unlawful to buy or sell a sacrament.
Obj. 4: Further, custom makes that which otherwise were sinful to be not sinful; thus Augustine says (Contra Faust. xxii, 47) that "it was no crime to have several wives, so long as it was the custom." Now it is the custom in some places to give something in the consecration of bishops, blessings of abbots, ordinations of the clergy, in exchange for the chrism, holy oil, and so forth. Therefore it would seem that it is not unlawful.
Obj. 5: Further, it happens sometimes that someone maliciously hinders a person from obtaining a bishopric or some like dignity. But it is lawful for a man to make good his grievance. Therefore it is lawful, seemingly, in such a case to give money for a bishopric or a like ecclesiastical dignity.