point — Wouters, Manual of Moral Theology
Point I. On the Notion, Division, and Necessity of Integrity
I. Notion. Integrity consists in this: that in confession someone declares those things which must be declared by him.
II. Division. Integrity is distinguished as twofold, material and formal. Material integrity is had when someone declares those things which of themselves must be declared; in other words, all mortal sins committed after Baptism and not yet duly declared and directly remitted (n. 294). Formal integrity is when someone declares those things which he is bound to declare here and now.
III. Necessity. 1. Material integrity is required of itself. This is clear first from these words of the Council of Trent: "From the already explained institution of the sacrament of Penance, the universal Church has always understood that the complete confession of sins was also instituted by the Lord, and that it exists as necessary by divine right for all who have fallen after Baptism"1 (cf. canon 901). Next, it is deduced from the fact that the sacrament of Penance was instituted after the manner of a judgment. But it belongs to a judge to have distinct knowledge of the matter - in the case, of sins - concerning which sentence is to be given; both lest he be constituted a blind instrument, and so that he can impose an equitable punishment.
Corollary. Material integrity is necessary by necessity of means. For, to apply to integral confession what we said of confession as such, it is necessary, as follows from what has been said, from the fact that the sacrament of Penance was instituted by Christ after the manner of a judgment. But what is required because of the nature of a sacrament instituted by Christ is necessary by necessity of means, because the sacrament itself is required by necessity of means.
- Accidentally, material integrity sometimes is not required in reality, namely if it is physically or morally impossible; in that case material integrity in desire, or formal integrity, suffices. This is deduced from the fact that otherwise the sacrament of Penance would have been instituted unfittingly. Hence the Council of Trent: "For it is established that nothing else is required in the Church from penitents than that, after each one has examined himself more diligently and has explored all the folds and hidden places of his conscience, he confess those sins by which he remembers that he mortally offended his Lord and God; but the remaining sins which do not occur to one thinking diligently are understood to be included universally in the same confession."2 And again: "If anyone shall say that in the sacrament of Penance for the remission of sins it is not necessary by divine right to confess all and individual mortal sins, of which memory is had with due and diligent premeditation... let him be anathema."3