Tertullian understood the apostle Paul to have suggested there would always be heretics (1 Cor. 11:19), and he presumed God had supplied scripture for their use. Without sacred literature heretics would have nothing of consequence to misread. Without contests over critical passages, there could be no winners, no losers—no heretics.1 The difficulty, Tertullian acknowledged, was that heretics were the poorest of losers; they never conceded defeat. He advised against trying to take (or take back) scripture passage by passage. The only way to get the best of heretics and get on with the work of interpreting texts correctly was to deny heretics' right to appeal to scripture.2 It had been supplied for them, but only to enable wayward expositors to identify themselves as heretics. This was Tertullian's version of “enough rope.” Heretics' expositions showed others how far the expositors deviated from the precious tradition originating with the apostles, and to assist those others apologists introduced a rule of faith condensing the apostles' instruction and tradition. Tertullian's several presentations of the rule of faith raise important questions; discrepancies prompt suspicion that no precise formulation or rule inspired consensus, that rules were rather makeshift. At the time, however, Tertullian obviously was more interested in another discrepancy, the one between his rule(s) expressing Christianity's incontrovertible truths and the opinions and exegesis of benighted heretics, for God provided heretics, apologists, and controversy to keep traditional or “regular” Christianity advancing on its proper course.3 Tertullian's confidence in the advance of Christianity is the subject of this paper. How did he come by it and just how did he relate the persistence of heresy to the progress of Christianity?