When quoting Tertullian on Heretics, one is always tempted to say “It takes one to know one”… Nevertheless, from the time when he was still an orthodox catholic Christian, here is an interesting snippet that I hadn’t come across before:
I must not omit an account of the conduct also of the heretics–how frivolous it is, how worldly, how merely human, without seriousness, without authority, without discipline, as suits their creed. To begin with, it is doubtful who is a catechumen, and who a believer; they have all access alike, they hear alike, they pray alike–even heathens, if any such happen to come among them.
…Simplicity they will have to consist in the overthrow of discipline, attention to which on our part they call brothelry. Peace also they huddle up anyhow with all comers; for it matters not to them, however different be their treatment of subjects, provided only they can conspire together to storm the citadel of the one only Truth.
All are puffed up, all offer you knowledge. Their catechumens are perfect before they are full-taught. The very women of these heretics, how wanton they are! For they are bold enough to teach, to dispute, to enact exorcisms, to undertake cures–it may be even to baptize.
Their ordinations, are carelessly administered, capricious, changeable. At one time they put novices in office; at another time, men who are bound to some secular employment; at another, persons who have apostatized from us, to bind them by vainglory, since they cannot by the truth.
Nowhere is promotion easier than in the camp of rebels, where the mere fact of being there is a foremost service. And so it comes to pass that to-day one man is their bishop, to-morrow another; to-day he is a deacon who to-morrow is a reader; to-day he is a presbyter who tomorrow is a layman. For even on laymen do they impose the functions of priesthood.”
Tertullian,On Prescription Against Heretics,41(c.A.D. 200),in ANF,III:263
The more things change, the more they stay the same, eh?