Catechesis: Justification

And it is furthermore false that reason by its own powers is able to love God above all things and to fulfill God’s law, namely, truly to fear God, truly to conclude that God hears prayer, willingly to obey God in death and in other visitations of God, and not to covet things that belong to others, etc.—although reason can produce civil works. It is also false and an affront to Christ to say that people who observe the commandments of God without grace do not sin.—Apology IV:27, 28