Article V: On the Obligation from a Precept of Obedience or Vow

382. The obligation of celebrating can arise from a special precept of obedience imposed by a legitimate superior. - Thus:

1. The Supreme Pontiff can command celebration of Mass for all priests, and the Bishop for priests subject to him, at least by reason of an office undertaken or to be fulfilled; indeed also the application for a determinate intention, which is not a merely internal act, but an internal act joined with an external one (I, n. 327).

2. Regular superiors can command their subjects, even in virtue of obedience, that they celebrate according to the intention established by them or prescribed by the constitutions, saving, however, exceptions sanctioned by the constitutions or by legitimate custom.

In this case, religious are also bound from justice, and indeed under grave sin, if stipends of Masses are accepted by superiors under this agreement, that they take care that Masses be celebrated through subjects; - on the contrary, if by force of dominative power superiors enjoin the application of Mass, or by force of constitutions they require a Mass to a certain intention, religious are bound only from obedience, gravely, lightly, or under penalty alone, according to the intention of the superior.

383. Observations. - 1. Besides the vow of religious obedience, from which someone, when a superior commands in virtue of obedience, can be held to celebrating Mass, one can oblige himself to this from a private vow; which obligation will be grave, unless the one vowing intended to oblige himself only under light sin.

2. A simple promise made to someone of offering the sacrifice for him obliges, provided that it is a true promise; nevertheless not under grave sin, unless someone expressly intended this.

3. A confessor can enjoin upon a penitent priest the celebration or application of Mass as a sacramental penance; in this case, unless he expressly says otherwise, he is presumed to require an application of Mass distinct and separate from every other obligation.