As noted earlier, church discipline is one of the marks of a true church. It is the duty of Christ's bride to purify herself from anything that would profane the Bridegroom. Private and public admonition, toward those who persist in sin, is a necessary function (Mt. l8:15-20; 1 Cor. 5:1-13). The Westminster Confession (XXXIV, 4) avers that the Holy Spirit is that member of the Trinity (economically speaking) by whom, "the church will be...purified."

Such discipline (church censures), says the Confession (XXX, 3), is necessary for: "the reclaiming and gaining of offending brethren; for the deterring of others from the like offences; for purging out of that leaven which might infect the whole lump; for vindicating the honour of Christ, and the holy profession of the gospel; and for preventing the wrath of God, which might justly fall upon the church, if they should suffer His covenant and the seals thereof, to be profaned by notorious and obstinate offenders."