Tertullian

“ Now if there are no heresies at all but what those who refute them are supposed to have fabricated, then the apostle who predicted them [7] must have been guilty of falsehood. If, however, there are heresies, they can be no other than those which are the subject of discussion. No writer can be supposed to have so much time on his hands [8] as to fabricate materials which are already in his possession. ”