Ecumenical councils Canon 21 of the
Fourth Council of the Lateran (1215), binding on the whole church, laid down the obligation of secrecy in the following words:
Gratian, who compiled the edicts of previous
Catholic Ecumenical Councils and the principles of church law, published the about 1151. It includes the following declaration of the law as to the seal of confession: "Let the priest who dares to make known the sins of his penitent be deposed." Gratian goes on to say that the violator of this law should be made a lifelong, ignominious wanderer. Notably, neither the Lateran canon nor the law of the purports to enact for the first time the secrecy of confession. The 15th-century
English canonist
William Lyndwood speaks of two reasons why a priest is bound to keep secret a confession, the first being on account of the
sacrament because it is almost (quasi) of the essence of the sacrament to keep secret the confession.
Thomist theology The devotes one article to the seal of confession, explaining that the seal may not be violated, including regarding matters that might indirectly lead to the seal's violation, not even violated by those who overhear the confession. Thomas gives two reasons for the seal's inviolability: the seal is divinely instituted and the seal prevents scandal.
Pope Pius X in his catechism taught that "the confessor is bound by the seal of confession under the gravest sin and under threat of the severest punishments both temporal and eternal." The
Catechism of the Catholic Church teaches in paragraph 1467: The
Compendium of the Catechism of the Catholic Church elaborates that a confessor is bound to secrecy.
Apostolic Penitentiary In
Note on the importance of the internal forum and the inviolability of the Sacramental Seal, the
Apostolic Penitentiary explained that the sacramental seal is universally and permanently
inviolable as a matter of
dogma, and as part of
freedom of religion and
freedom of conscience, despite civil law. ==In practice==