The Five Books Against Marcion by Tertullian
Chapter VIII.--Specific Points. The Novelty of Marcion's God Fatal to His Pretensions God is from Everlasting, He Cannot Be in Any Wise New.
In the first place, how arrogantly do the Marcionites build up their stupid system, bringing forward a new god, as if we were ashamed of the old one! So schoolboys are proud of their new shoes, but their old master beats their strutting vanity out of them. Now when I hear of a new god, who, in the old world and in the old time and under the old god was unknown and unheard of; whom, (accounted as no one through such long centuries back, and ancient in men's very ignorance of him), a certain |Jesus Christ,| and none else revealed; whom Christ revealed, they say -- Christ himself new, according to them, even, in ancient names -- I feel grateful for this conceit of theirs. For by its help I shall at once be able to prove the heresy of their tenet of a new deity. It will turn out to be such a novelty as has made gods even for the heathen by some new and yet again and ever new title for each several deification. What new god is there, except a false one? Not even Saturn will be proved to be a god by all his ancient fame, because it was a novel pretence which some time or other produced even him, when it first gave him godship. On the contrary, living and perfect Deity has its origin neither in novelty nor in antiquity, but in its own true nature. Eternity has no time. It is itself all time. It acts; it cannot then suffer. It cannot be born, therefore it lacks age. God, if old, forfeits the eternity that is to come; if new, the eternity which is past. The newness bears witness to a beginning; the oldness threatens an end. God, moreover, is as independent of beginning and end as He is of time, which is only the arbiter and measurer of a beginning and an end.