Matthew 18 Is Not Acts 15: Church Conflict, Classis, Synod, and Theological Discernment

At some point in church conflict, someone usually asks, "Have you followed Matthew 18?"

 As a pastor, I've heard that question often, usually after someone asks me to confront another person on their behalf. My first response is almost always, "Have you talked to them?" Jesus' first instruction is not to involve a pastor, elder, or council. It is to go directly to the person.

Matthew 18:15 says,  “If your brother or sister sins, go and point out their fault, just between the two of you.” If the person listens, “you have won them over.” If not, one or two others are brought along so that the matter can be established truthfully. If there is still no repentance, the church becomes involved. The goal throughout the chapter is restoration. Peter’s question about forgiveness later in the chapter (Matthew 18:21) serves to further reinforce that point.

But Matthew 18 is not the only biblical text about conflict in the church.

In Acts 15, Paul and Barnabas are not responding to a personal offense but to a public theological claim: that Gentile believers must be circumcised to be saved. Because this issue was a big deal - it concerned the very Gospel itself! - it could not be resolved through a private Matthew 18 conversation. So the matter was brought before the apostles and elders in Jerusalem. Notably, however, Paul was not personally offended; he was responding, again, to a significant theological issue. 

Acts 15 says there was “much discussion” (verse 7). Peter spoke. Paul and Barnabas shared what God had done among the Gentiles. James turned to Scripture. Then the apostles and elders, with the whole church, sent representatives and a letter back to Antioch. The letter was clear: some had gone out “without our authorization” and had disturbed the believers by what they said (Acts 15:24).

That is the church doing theological discernment.

I have seen how easily these two categories get mixed together. A public theological statement is made, and a church, council, classis, or synod is asked to evaluate it. But instead of staying with the theological question, the conversation shifts. Suddenly the issue becomes whether someone felt hurt, betrayed, unsafe, or personally attacked.

I care when people are hurt or feel unheard. But sometimes the language of personal offence is used to avoid a public theological question. If a teaching has been made, written, or defended publicly, then the broader church may need to respond publicly. That is not automatically a Matthew 18 failure. It may be an Acts 15 responsibility.

Being upset by a theological judgment is not the same thing as being sinned against, as in the Matthew 18 sense.

Our Reformed confessions recognize both responsibilities. Belgic Confession Article 29 identifies faithful gospel preaching and church discipline as marks of the true church, while Heidelberg Catechism Lord's Day 31 reminds us that discipline is one of the keys of the kingdom. Guarding the gospel and restoring sinners belong together.

That is also why Reformed churches have councils, classes, and synods. These assemblies are not supposed to replace local pastoral care or turn every argument into a denominational case file. But they do give the churches a broader table when the issue is larger than one person, one conversation, or one local congregation.

Classis and synod can help when public theological questions need to be tested by Scripture and confession. They can help churches listen together. They can keep one congregation from becoming a law unto itself. They can also give clarity when clarity is needed.

Of course, they can also do harm. Procedures can be used like weapons. People can be treated like problems to solve instead of brothers and sisters in Christ. A classis or synod can be too afraid to name false teaching, or too eager to win a fight. Neither is faithful.

So yes, when the issue is personal sin, we should ask, “Have we followed Matthew 18?” Have we gone directly, spoken truthfully and avoided gossip? 

But when the issue is public teaching, doctrine, confession, and the gospel, we should also ask, “Is this actually an Acts 15 issue?” Does this need broader discernment?

Matthew 18 keeps personal reconciliation from becoming a public spectacle. Acts 15 keeps public truth from being reduced to personal offence.

The church needs both: the courage to go to a brother or sister, and the courage to guard the gospel together.