Diversity of Doctrine Means Corruption of Scriptures

Where diversity of doctrine is found, there, then, must the corruption both of the Scriptures and the expositions thereof be regarded as existing. On those whose purpose it was to teach differently, lay the necessity of differently arranging the instruments of doctrine. They could not possibly have effected their diversity of teaching in any other way than by having a difference in the means whereby they taught. As in their case, corruption in doctrine could not possibly have succeeded without a corruption also of its instruments, so to ourselves also integrity of doctrine could not have accrued, without integrity in those means by which doctrine is managed.

Tertullian, On Prescription Against Heretics, chapter XXXVIII