They went out from us, but they were not really of us; for if they had been of us, they would have remained with us; but they went out, so that it would be shown that they all are not of us. 1 John 2:19, NASB
19 Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness, 20 Idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies, 21 Envyings, murders, drunkenness, revellings, and such like:of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God. Galatians 5:19-21, KJV
In the passage from Galatians, which I placed above, at the end of v. 20 is the word “heresies.” The NASB translates this same word as “factions.” It is a form of the word αἵρεσις or hairesis, which is only theoretical in that one can hold different views than the majority and remain in the same body but he is a heretic. Heresy is theoretical and does not become practical until the heretic tears himself away, σχίζω or schizō. Then he is schismatic and is the source of σχίσμα or schisma. In that, schismaticalness is practical heresy.