“Moreover, if your brother commits a sin, go lay bare his fault between you and him alone. If he listens to you, you have gained your brother. But if he does not listen, take along with you one or two more, in order that at the mouth of two or three witnesses every matter may be established. If he does not listen to them, speak to the congregation. If he does not listen even to the congregation, let him be to you just as a man of the nations and as a tax collector.”​—Matthew 18:15-17.

If the matter could not be settled, it was to be taken to the congregation. Initially, this meant the elders of the Jews but later, the elders of the Christian congregation. The unrepentant wrongdoer may have to be expelled from the congregation. That is what is meant by considering him “just as a man of the nations and as a tax collector,” individuals from whom the Jews kept their distance. This serious measure could not be taken by any Christian individually. The appointed elders, who represent the congregation, are the only ones authorized to take such action.​—Compare 1 Corinthians 5:13.

The possibility of an unrepentant wrongdoer being disfellowshipped shows that Matthew 18:15-17 does not pertain to minor differences. Jesus was referring to serious offenses, yet of the type that might be settled between just the two individuals concerned. For example, the offense might be slander, seriously affecting the victim’s reputation. Or it might pertain to financial matters, for succeeding verses contain Jesus’ illustration of the merciless slave who had been forgiven a great debt. (Matthew 18:23-35) A loan not repaid in the allotted time might be just a passing difficulty that could easily be resolved between the two individuals. But it could become a serious sin, namely, theft, if the borrower obstinately refused to repay what was owed.

Other sins cannot be settled simply between two Christians. Under the Mosaic Law, serious sins were to be reported. (Leviticus 5:1; Proverbs 29:24) Similarly, gross sins involving the purity of the congregation have to be reported to Christian elders.

However, most cases of friction between Christians do not come under this procedure.