Eunomius the Anomœan, bp. of Cyzicus, against whose Liber Apologeticus Basil wrote his counter-work.  The first appearance of the αἱρετικὸς ἄνθρωπος, the “chooser” of his own way rather than the common sense of the Church, is in Tit. iii. 10.  αἱρετίζειν is a common word in the LXX., but does not occur in Is. xlii. 1, though it is introduced into the quotation in Matt. xii. 18.  ἅιρεσις is used six times by St. Luke for “sect;” twice by St. Paul and once by St. Peter for “heresy.”  Augustine, C. Manich. writes:  “Qui in ecclesia Christi morbidum aliquid pravumque quid sapiunt, si, correcti ut sanum rectumque sapiant, resistunt contumaciter suaque pestifera et mortifera dogmata emendare nolunt, sed defensare persistunt hæretici sunt.”