Magistrates, who should know theology and should have the law before their eyes (Deut. 17:18–20; Josh. 1:8; Psalm 19), prescribe it for their subordinates (2 Chron. 17:7–9; Josh. 24:14ff.), protect it against enemies, as nursing fathers of the church (Isa. 49:23; 60:16) and as guardians of both tables of the law, and propagate it (Gen. 18:19).147 In sum they should, in all these ways, kiss Christ (Ps. 2:10–12), so that their polity becomes a theocracy, that is, a Christocracy.

PETRUS VAN MASTRICHT, THEORETICAL-PRACTICAL THEOLOGY, VOLUME 1: PROLEGOMENA, 234.

Who is obligated [to cast out false theology]?

This duty is incumbent on (1) preachers of Christian truth (Titus 3:10–11; Acts 15:2; Gal. 2:11, 14); (2) the magistrate (2 Kings 10:25), to whom it was formerly prescribed to resist false theology, even with capital punishment (Deut. 13:5; 18:20; 1 Kings 18:40); and (3) whoever has professed Christian truth (Matt. 7:15; Rom. 16:17; 2 Thess. 3:14; 2 Tim. 2:16–17; Titus 3:10–11; 2 John 10).

Reasons for these things Indeed, false theology must be resisted because it (1) strives to overturn the gospel of Christ (Gal. 1:7); (2) blasphemes the way of truth (2 Peter 2:2); (3) bewitches people so that they do not yield to the truth (Gal. 3:1); (4) ransacks churches (Acts 15:24; Gal. 1:7; 5:10, 12); (5) is destructive (2 Peter 2:2–3); and (6) is hateful to Christ (Rev. 2:6, 15).

PETRUS VAN MASTRICHT, THEORETICAL-PRACTICAL THEOLOGY, VOLUME 1: PROLEGOMENA, 232.

Christian theology is best defined as the doctrine of living for God through Christ.

Petrus van Mastricht, Theoretical-Practical Theology, Volume 1: Prolegomena, 208.