Catechesis: Confession

Here you see that Baptism, both in its power and meaning, includes also the third Sacrament, which has been called repentance... What is repentance but a serious attack on the old man, that his lusts be restrained, and an entering into a new life? Therefore, if you live in repentance, you walk in Baptism.—LC IV:74, 75

I say this lest we fall into the opinion in which we were stuck for a long time. We were imagining that our Baptism is something past, which we can no longer use after we fall again into sin.—LC IV:80

Therefore, if we have received forgiveness of sins once in Baptism, it will remain every day, as long as we live. Baptism will remain as long as we carry the old man about our neck.—LC IV:86