Between a Rock and a Hard Place

Since the force of this will act is so great that in satisfying us with its own gratification it takes the place of the deed, it follows that it will be punished in place of the deed. It is sheer folly to say, "I willed, but I did not act." Rather you should complete the act, since you will it; or you should not will it at all, since you are not going to complete it. Actually, you condemn yourself by the confession of your conscience, for if you desired a thing that was good you would have tried to carry it through to completion; if, on the other hand, you fail to carry it through to completion because it is evil, you ought not even to desire it. Whatever position you take, guilt holds you fast, for you have either willed what is evil, or you have failed to accomplish what is good.

Tertullian, On Penitence