Catechism of the Catholic Church

With bold confidence, we began praying to our Father. In begging him that his name be hallowed, we were in fact asking him that we ourselves might be always made more holy. But though we are clothed with the baptismal garment, we do not cease to sin, to turn away from God. Now, in this new petition, we return to him like the prodigal son and, like the tax collector, recognize that we are sinners before him. Our petition begins with a "confession" of our wretchedness and his mercy. Our hope is firm because, in his Son, "we have redemption, the forgiveness of sins." We find the efficacious and undoubted sign of his forgiveness in the sacraments of his Church. (1425, 1439, 1422)