Tertullian

“ Else how absurd it would be, that, when we have proved our position to be the older one, and Marcion’s the later, ours should yet appear to be the false one, before it had even received from truth its objective existence ”

“ Marcion, that his is. I affirm that Marcion’s Gospel is adulterated; Marcion, that mine is. Now what is to settle the point for us, except it be that principle [2] of time, which rules that the authority lies with that which shall be found to be more ancient; and assumes as an elemental truth, [3] that corruption (of doctrine) belongs to the side which shall be convicted of comparative lateness in its origin. [4] For, inasmuch as error [5] is falsification of truth, it must needs be that truth therefore precede error. A thing must exist prior to its suffering any casualty ”