her'-e-si, her'-e-si (hairesis, from verb haireo, "to choose"):
The word has acquired an ecclesiastical meaning that has passed into common usage, containing elements not found in the term in the New Testament, except as implied in one passage. In classical Greek, it may be used either in a good or a bad sense, first, simply for "choice," then, "a chosen course of procedure," and afterward of various schools and tendencies. Polybius refers to those devoting themselves to the study of Greek literature as given to the Hellenike hairesis. It was used not simply for a teaching or a course followed, but also for those devoting themselves to such pursuit, namely, a sect, or assembly of those advocating a particular doctrine or mode of life. Thus, in Acts, the word is used in the Greek, where the King James Version and the Revised Version (British and American) have "sect," "sect of the Sadducees" (Acts 5:17), "sect of the Nazarenes" (Acts 24:5). In Acts 26:5 the Pharisees are called "the straitest hairesis (sect)." The name was applied contemptuously to Christianity (Acts 24:14; 28:22). Its application, with censure, is found in 1 Corinthians 11:19 m; Galatians 5:20 margin, where it is shown to interfere with that unity of faith and community of interests that belong to Christians. There being but one standard of truth, and one goal for all Christian life, any arbitrary choice varying from what was common to all believers, becomes an inconsistency and a sin to be warned against. Ellicott, on Galatians 5:20, correctly defines "heresies" (King James Version, the English Revised Version) as "a more aggravated form of dichostasia" (the American Standard Revised Version "parties") "when the divisions have developed into distinct and organized parties"; so also 1 Corinthians 11:19, translated by the Revised Version (British and American) "factions." In 2 Peter 2:1, the transition toward the subsequent ecclesiastical sense can be traced. The "destructive heresies" (Revised Version margin, the English Revised Version margin "sects of perdition") are those guilty of errors both of doctrine and of life very fully described throughout the entire chapter, and who, in such course, separated themselves from the fellowship of the church.
In the fixed ecclesiastical sense that it ultimately attained, it indicated not merely any doctrinal error, but "the open espousal of fundamental error" (Ellicott on Titus 3:10), or, more fully, the persistent, obstinate maintenance of an error with respect to the central doctrines of Christianity in the face of all better instruction, combined with aggressive attack upon the common faith of the church, and its defenders. Roman Catholics, regarding all professed Christians who are not in their communion as heretics, modify their doctrine on this point by distinguishing between Formal and terial Heresy, the former being unconscious and unintentional, and between different degrees of each of these classes (Cath. Encyclopedia, VII, 256). For the development of the ecclesiastical meaning, see Suicer's Thesaurus Ecclesiasticus, I, 119-23.
H. E. Jacobs