Catechesis: Concerning Confession

Concerning confession it is taught that private absolution should be retained and not abolished. However, it is not necessary to enumerate all misdeeds and sins, since it is not possible to do so. Ps. 19: “But who can detect their errors?”—AC XI

Canon 21 of Lateran IV:

All the faithful of both sexes shall after they have reached the age of discretion faithfully confess all their sins at least once a year to their own (parish) priest and perform to the best of their ability the penance imposed, receiving reverently at least at Easter the sacrament of the Eucharist, unless perchance at the advice of their own priest they may for a good reason abstain for a time from its reception; otherwise they shall be cut off from the Church (excommunicated) during life and deprived of Christian burial in death.