Titus 3:10-11 A man that is an heretic after the first and second admonition reject; Knowing that he that is such is subverted, and sinned, being condemned of himself. 

‘Heretic’ [Greek, hairetikos] one who maintains opposition to truth; a choosing, hence, a sect (Acts 5:17; 15:5; 24:5; 26:5; 28:22) and heresy (Acts 24:14; 1Cor. 11:19; Gal. 5:20; 2Pet. 2:1). The word itself has no evil meaning. It simply refers to a doctrinal view or belief at variance with the recognized and accepted tenets of a system, church, or party. The word heretic is used once in Scripture (3:10) and means one who holds a heresy; a dissenter, or a nonconformist. It only takes on an evil meaning when sound doctrine is rejected and fallacy is accepted and taught in preference to the truth. If the doctrine is unsound and one dissent from the main body that holds the fallacy, then he is a heretic in a good sense.

The word signifies a sect or party, whether good or bad, distinguished from all other sects and parties. It formerly was applied to different sects of heathen philosophers. The church of Rome uses it only in an evil sense to apply to all who cannot go along with their many dogmas and rituals that have been added for many centuries to the pure teachings of the Christian faith. A heretic to them is not a papist, and because of this is outside the Christian religion. Almost all denominations use it in the same sense as those who do not see eye to eye with them. True Christians apply it to all false religions that do not accept true Christian doctrines and follow and obey Jesus Christ. Jews called Christians a sect (Acts 24:5, 14; 28:22) and Christians called the Pharisees and Sadducees and other groups sects (Acts 5:17; 15:5; 26:5). All deviation from the truth is heresy (Gal. 5:20; 1Cor. 11:19; 2Pet. 2:1).

‘Reject’ [Greek, paraiteomai] beg off. Translated as “reject” (3:10); “avoid” (2Tim. 2:23); “entreat” (Heb. 12:19); “make excuse” (Luke 14:18); and “refuse” (Acts 25:11; 1Tim. 4:7; 5:11; Heb. 12:25).

‘Knowing that he that is such is subverted, and sinned, being condemned of himself.’ Three effects of heresy: [1] Subversion, to turn out of how one may be saved. [2] Sin [Greek, harmartano] miss a mark or aim; to wander from the right path that leads to life; go in the path of destruction. Translated “sin” 32 times (3:11; Matt. 18:21; 27:4; Luke 15:18-21; John 5:14; 8:11; 9:2-3; Rom. 2:12; 3:23; 5:12-16; 6:15; 1Cor. 6:18; 7:28, 36; 8:12; 15:34; Eph. 4:26; 1Tim. 5:20; Heb. 3:17; 10:26; 2Pet. 2:4; 1Jn. 1:10; 2:1; 3:6-9; 5:16-18); “to trespass” (Matt. 18:15; Luke 17:3-4); “offend” (Acts 25:8); and “faults” (1Pet. 2:20). [3] Self-condemnation.