27. Before the good a man does is the good of charity, evil must first be put away, because it is contrary to charity; and this is done by repentance.
Since evil must first be known for the reason that it is to be put away, the Decalogue was the "first" of the Word, and in the whole of Christendom is also the " first " of the doctrine of the Church. All are initiated into the Church through knowing evil, and, because it is against God, not doing it.