Ante-Nicene Fathers, Vol III:
Tertullian: Part II: Jesus Christ, the Revealer of the Creator, Could Not Be the Same as Marcion's God, Who Was Only Made Known by the Heretic Some CXV. Years After Christ, and That, Too, on a Principle Utterly Unsuited to the Teaching of Jesus Christ, I.e., the Opposition Between the Law and the Gospels.

Chapter XIX.—Jesus Christ, the Revealer of the Creator, Could Not Be the Same as Marcion’s God, Who Was Only Made Known by the Heretic Some CXV. Years After Christ, and That, Too, on a Principle Utterly Unsuited to the Teaching of Jesus Christ, I.e., the Opposition Between the Law and the Gospels.

Well, but our god, say the Marcionites, although he did not manifest himself from the beginning and by means of the creation, has yet revealed himself in Christ Jesus. A book will be devoted 2545 to Christ, treating of His entire state; for it is desirable that these subject-matters should be distinguished one from another, in order that they may receive a fuller and more methodical treatment. Meanwhile it will be sufficient if, at this stage of the question, I show—and that but briefly—that Christ Jesus is the revealer 2546 of none other god but the Creator. In the fifteenth year of Tiberius, 2547 Christ Jesus vouchsafed to come down from heaven, as the spirit of saving health. 2548 I cared not to inquire, indeed, in what particular year of the elder Antoninus.  He who had so gracious a purpose did rather, like a pestilential sirocco, 2549 exhale this health or salvation, which Marcion teaches from his Pontus. Of this teacher there is no doubt that he is a heretic of the Antonine period, impious under the pious. Now, from Tiberius to Antoninus Pius, there are about 115 years and 6-1/2 months.  Just such an interval do they place between Christ and Marcion. Inasmuch, then, as Marcion, as we have shown, p. 285 first introduced this god to notice in the time of Antoninus, the matter becomes at once clear, if you are a shrewd observer. The dates already decide the case, that he who came to light for the first time 2550 in the reign of Antoninus, did not appear in that of Tiberius; in other words, that the God of the Antonine period was not the God of the Tiberian; and consequently, that he whom Marcion has plainly preached for the first time, was not revealed by Christ (who announced His revelation as early as the reign of Tiberius). Now, to prove clearly what remains of the argument, I shall draw materials from my very adversaries. Marcion’s special and principal work is the separation of the law and the gospel; and his disciples will not deny that in this point they have their very best pretext for initiating and confirming themselves in his heresy. These are Marcion’s Antitheses, or contradictory propositions, which aim at committing the gospel to a variance with the law, in order that from the diversity of the two documents which contain them, 2551 they may contend for a diversity of gods also.  Since, therefore, it is this very opposition between the law and the gospel which has suggested that the God of the gospel is different from the God of the law, it is clear that, before the said separation, that god could not have been known who became known 2552 from the argument of the separation itself.  He therefore could not have been revealed by Christ, who came before the separation, but must have been devised by Marcion, the author of the breach of peace between the gospel and the law.  Now this peace, which had remained unhurt and unshaken from Christ’s appearance to the time of Marcion’s audacious doctrine, was no doubt maintained by that way of thinking, which firmly held that the God of both law and gospel was none other than the Creator, against whom after so long a time a separation has been introduced by the heretic of Pontus.

Footnotes

The third of these books against Marcion.

Circumlatorem.

The author says this, not as his own, but as Marcion’s opinion; as is clear from his own words in his fourth book against Marcion, c. 7, (Pamelius).

Spiritus salutaris.

Aura canicularis.

Primum processit.

Utriusque instrumenti.

Innotuit.