The keys of the kingdom have been entrusted by Christ to the elders of His church (Mt. 16:19). With these keys, the officers of the church have the power to retain or remit sins, to shut out the door to the kingdom or to open it up that any would enter (WCF 30.2). The first way of exercising this responsibility is through the preaching of the Word, which we have already considered. The second way is by practicing church discipline. 

In Matthew 18, Christ lays out the ways in which the church should respond to obstinate sinners in its midst. If the man or woman does not respond to private admonition or confrontation with witnesses (18:15–16), then the matter is to be taken to the church (18:17a). And if the person refuses to listen to the church, they are to be treated as Gentiles and tax collectors—excommunicated from God’s people (18:17b). For “whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven” (18:18, see also Jn. 20:21–23). This entire process outlined here would apply to private sins—“if your brother sins against you” (18:15). Regarding public sins, St Paul instructs Timothy to rebuke the person in the presence of all, so that observers would fear (1 Tim. 5:20).

This practice of excommunication is sadly neglected in today’s church. And when spoken of, those unfamiliar with the practice tend to view it as “unloving” or cult-like. Therefore, it would do well to touch on this important role of discipline in pastoral ministry and why it is an important and actually loving practice.