2262. Cessation of Obligation of Promissory Oath.—The obligation of a promissory oath, like that of a vow (see 2226), ceases intrinsically or extrinsically.
(a) Intrinsically, an oath ceases when there is a substantial change in the matter (e.g., it is or has become impossible or unlawful, as in Herod’s oath to Salome), when the principal reason for the oath has ceased (e.g., Titus swore to give an alms to Sempronius because the latter was poor, but before the alms was given Sempronius became rich), or when the time or condition by which the oath was limited terminates the obligation.
(b) Extrinsically, an oath ceases by condonation (e.g., when the State or a private person to whom a sworn promise has been made yields the right and remits the obligation), by annulment (e.g., when a father nullifies the oath of his minor child), by dispensation (e.g., when the Church absolves from an oath taken under grave compulsion), by commutation (e.g., when the Church changes the matter of a sworn vow into something more suitable). Those who can annul, dispense or commute vows have the same power over oaths; but if the dispensation of an oath is detrimental to others who are unwilling to forego the promise, only the Apostolic See can dispense, and then on account of a necessary reason (see Canon 1320).
2263. Adjuration.—Adjuration is the invocation of the name of God used in a request or command to another person in order to move that person to do or omit something.
(a) It is an invocation, and in this respect it is like an oath, for both an oath and an adjuration call upon the name of God.
(b) It calls upon the name of God either explicitly (e.g., “I command you in the name of God”) or implicitly (e.g., “I beseech you for the sake of the passion of Christ”). If command or request is made in the name of a creature and without reference to God’s attributes reflected in them, there is not, properly speaking, an adjuration, as when one implores a favor from another person in the name of a Patron Saint, or of one’s country, parents, friendship, etc.
(c) It is used in a command or a request, and thus it differs from prayer, which cannot be made in the form of a command. But adjuration may be used in prayers to God Himself or to the Saints, as is done in obsecrations.
(d) Its purpose is to move another to an act or omission, and thus it is different from an oath. The end of an oath is to confirm one’s words by the testimony of God; the end of an adjuration is to influence another to a certain course through an appeal to his respect, fear or love of God.
2264. The Species of Adjuration.—(a) Adjuration is solemn or simple (private). The solemn adjuration is made in the name of the Church by her ministers and in the ritual form prescribed by her, as in the exorcisms of Baptism. The simple adjuration is made by private persons and without ritual ceremony.
(b) Adjuration is imperative or deprecative. The imperative is given in the form of a command to inferiors or demons, as when St. Paul writes to the Thessalonians: “I charge you by the Lord that this epistle be read” (I Thess., v. 27). The deprecative is given in the form of a request made to God or to any creature not damned, as when St. Paul writes to the Romans: “I beseech you, brethren, by the love of God that you present your bodies a living sacrifice” (Rom., xii. 1).