Theory and practice of the confessional by Caspar Erich Schieler, Richard Frederick Clarke
ESSENCE, NECESSITY, AND PROPERTIES OP CONFESSION
19. Essence and Necessity of Confession.
Though contrition is the most important of the dispositions which a penitent must bring to the Sacrament, the confessing of the sins is the most prominent feature to ordinary observers; hence the Sacrament is often simply called confession, as in the very earliest ages of the Church it was known simply as confessio (in Greek exomologesis).
Sacramental confession is the self-accusation of sins committed after Baptism and not yet remitted in the Sacrament, and it is made by the penitent to a priest having the necessary faculties and with the object of obtaining absolution.
Hence it is not a sacramental confession when the sins are told enarratione mere historica; such a recital would not be an accusation, nor would it be done with the view of acknowledging one's self a sinner or of obtaining absolution. Moreover, it is not a sacramental confession if sins are revealed to a priest to obtain counsel or help from him, or if they are told to the priest merely in derision, for there would be no accusation in this, at least it would not be done with a view of obtaining absolution. On the contrary, a confession invalid through any defect whatever would be sacramental if it was made in order to obtain absolution.
If, however, a man began by simply relating his sins to an authorised priest without any idea of making a sacramental confession, and then in order to obtain absolution accuses himself in general terms to the same priest of those same sins, the confession would be sacramental, for then a formal accusation would be made of those sins to the priest as judge, in order that absolution might be given.
The necessity of this confession for all mortal sins committed after Baptism is a dogma of the Church, and rests on the divine institution of the Sacrament. The proof is to be sought in dogmatic treatises. In the divine institution of this Sacrament, as a necessary means for obtaining forgiveness of sin by confession to a priest, is included the divine command of confessing sin, which binds all who have committed mortal sin after Baptism. We have already spoken of this in treating of the duty of approaching the Sacrament, since confession is one of the acts required of the penitent on receiving this Sacrament.
There remains yet another point which shows the necessity of confession. Perfect contrition, as we have seen above, remits sin apart even from the Sacrament, but it does not remove the obligation of mentioning the sins so remitted to a duly authorized priest. The obligation remains, because by Christ's command every mortal sin committed after Baptism must be submitted by confession to the power of the keys. This follows from the words of Our Lord (John xx. 23); hence the Council of Trent teaches that for those who have fallen into mortal sin after Baptism confession is as necessary as Baptism is to those who have not been baptized.