Against Marcion

But even if we were able to allow that he exists, we should yet be bound to argue that he is without a cause. For he who had nothing (to show for himself as proof of his existence), would be without a cause, since (such) proof is the whole cause that there exists some person to whom the proof belongs. Now, in as far as nothing ought to be without a cause, that is, without a proof (because if it be without a cause, it is all one as if it be not, not having the very proof which is the cause of a thing), in so far shall I more worthily believe that God does not exist, than that He exists without a cause.

For he is without a cause who has not a cause by reason of not having a proof. God, however, ought not to be without a cause, that is to say, without a proof. Thus, as often as I show that He exists without a cause, although (I allow that) He exists, I do really determine this, that He does not exist; because, if He had existed, He could not have existed altogether without a cause. So, too, even in regard to faith itself, I say that he seeks to obtain it without cause from man, who is otherwise accustomed to believe in God from the idea he gets of Him from the testimony of His works: (without cause, I repeat,) because he has provided no such proof as that whereby man has acquired the knowledge of God.

For although most persons believe in Him, they do not believe at once by unaided reason, without having some token of Deity in works worthy of God. And so upon this ground of inactivity and lack of works he is guilty both of impudence and malignity: of impudence, in aspiring after a belief which is not due to him, and for which he has provided no foundation; of malignity, in having brought many persons under the charge of unbelief by furnishing to them no groundwork for their faith.