Tertullian

“ If you intimate to them that you understand their opinions, they insist on knowing nothing themselves. If you come to a close engagement with them they destroy your own fond hope of a victory over them by a self-immolation. ”

“ The Valentinians, who are no doubt a very large body of heretics—comprising as they do so many apostates from the truth, who have a propensity for fables, and no discipline to deter them (therefrom) care for nothing so much as to obscure [1] what they preach, if indeed they (can be said to) preach who obscure their doctrine. The officiousness with which they guard their doctrine is an officiousness which betrays their guilt. ”

“ Not even to their own disciples do they commit a secret before they have made sure of them. They have the knack of persuading men before instructing them; although truth persuades by teaching, but does not teach by first persuading. ”