The Five Books Against Marcion by Tertullian
Chapter XVII.--Not Enough, as the Marcionites Pretend, that the Supreme God Should Rescue Man; He Must Also Have Created Him. The Existence of God Proved by His Creation, a Prior Consideration to His Character.
Pressed by these arguments, they exclaim: One work is sufficient for our god; he has delivered man by his supreme and most excellent goodness, which is preferable to (the creation of) all the locusts. What superior god is this, of whom it has not been possible to find any work so great as the man of the lesser god! Now without doubt the first thing you have to do is to prove that he exists, after the same manner that the existence of God must ordinarily be proved -- by his works; and only after that by his good deeds. For the first question is, Whether he exists? and then, What is his character? The former is to be tested by his works, the other by the beneficence of them. It does not simply follow that he exists, because he is said to have wrought deliverance for man; but only after it shall have been settled that he exists, will there be room for saying that he has affected this liberation. And even this point also must have its own evidence, because it may be quite possible both that he has existence, and yet has not wrought the alleged deliverance. Now in that section of our work which concerned the question of the unknown god, two points were made clear enough -- both that he had created nothing: and that he ought to have been a creator, in order to be known by his works; because, if he had existed, he ought to have been known, and that too from the beginning of things; for it was not fit that God should have lain hid. It will be necessary that I should revert to the very trunk of that question of the unknown god, that I may strike off into some of its other branches also. For it will be first of all proper to inquire, Why he, who afterwards brought himself into notice, did so -- so late, and not at the very first? From creatures, with which as God he was indeed so closely connected (and the closer this connection was, the greater was his goodness), he ought never to have been hidden. For it cannot be pretended that there was not either any means of arriving at the knowledge of God, or a good reason for it, when from the beginning man was in the world, for whom the deliverance is now come; as was also that malevolence of the Creator, in opposition to which the good God has wrought the deliverance. He was therefore either ignorant of the good reason for and means of his own necessary manifestation, or doubted them; or else was either unable or unwilling to encounter them. All these alternatives are unworthy of God, especially the supreme and best. This topic, however, we shall afterwards more fully treat, with a condemnation of the tardy manifestation; we at present simply point it out.