Is Matthew 18 Church Discipline?

Matthew 18 is not a teaching how to conduct general discipline in the local church, it is teaching how individual members must resolve personal conflict. Church discipline is conducted by the elders and involves processes not encompassed by Matthew 18, but found elsewhere in scripture. The phrase, "tell it unto the church" in verse 17 does not restrict the practicality of this teaching to the local church, it is not that limited or narrow. It is helpful to recognize that "church" means "a called out" group, that is, a group of a specific kind of association. This perspective gives greater latitude in application and also gives clarity helpful to varied circumstances.

Every relationship has a context that indicates those who are "called out" as a part of that relationship, those who are in association in that context are "your brother". It is the context of a relationship that governs the application of Matthew 18. If your children are involved in a local 4-H club, and a matter arises in that club that requires conciliation, the "church" would be the club or representatives designated by that club and organization to which one would appeal for resolution. You wouldn't bring a club policy or decision to your local church just because you are Christians (though you would if things got out of hand and affected the harmony of the church). Practically, then, "church" means a limited group that for a common purpose is "called out" of a more general group. The purpose is defined by the common interests and forms the basis for defining who belongs and how to appeal trespasses. In this sense, a "heathen and publican" would be a non-member of your  collective group, i.e. someone with no standing in your group.

Obviously Christ was focused upon the "called out" assembly of the saints in this teaching. However, this simple clarification of "church" directs our attention more closely to the fact that Matt. 18 is teaching individual members how to resolve conflicts that arise between them. Failure to resolve personal matters can eventually lead to separating the offending party from the whole local church. This is not church discipline per se, but conflict resolution resulting in a final collective decision of the whole church over a personal matter between individuals.

It is worth mentioning that a "church" or a "called out" group of individuals has a simpler application than what is often assumed in the phrase, "tell it unto the church". Paul instructed the Corinthians to create a "called out" body within the larger "church" to handle Matthew 18 type of church matters. 1Corinthians 6:1, 4-5 says, "Dare any of you, having a matter against another, go to law before the unjust, and not before the saints? …If then ye have judgments of things pertaining to this life, set them to judge who are least esteemed in the church. I speak to your shame. Is it so, that there is not a wise man among you? no, not one that shall be able to judge between his brethren?" In the context of the larger community of the church, there is an obligation to "call out" a smaller group of individuals who can hear and judge matters of conflict within the local church. This "church" judgment is binding on all parties to the point of suffering personal loss ending a conflict, or being removed from the larger church body.

This designated or "called out" subgroup of the larger church group is what Matthew 18 refers to. There is no biblical evidence that envisions bringing the whole collective church together as one body to hear a matter of conflict as in an open court or open forum. Paul's method not only gives reasonable and practical means of solving conflict in the church body, but it also helps  to shift the focus upon the process of personal reconciliation that is clearly brought to an end so the unity of the body is not jeopardized, and the name of Christ is not shamed.