Tell it to the church - See the notes at Matthew 16:18. The church may here mean the whole assembly of believers, or it may mean those who are authorized to try such cases - the representatives of the church, or these who act for the church. In the Jewish synagogue there was a bench of elders before whom trials of this kind were brought. It was to be brought to the church in order that he might be admonished, entreated, and, if possible, reformed. This was, and is always to be, the first business in disciplining an offending brother.
But if he neglect to hear the church, let him be ... - The Jews gave the name “heathen” or “Gentile” to all other nations but themselves. With them they had no religious contact or communion.
Publican - See the notes at Matthew 5:47. Publicans were people of abandoned character, and the Jews would have no contact with them. The meaning of this is, cease to have religious contact with him, or to acknowledge him as a Christian brother. It does not mean that we should cease to show kindness to him and aid him in affliction or trial, for that is required toward all people; but it means that we should disown him as a Christian brother, and treat him as we do other people not connected with the church. This should not be done until all these steps are taken. This is the only way of kindness. This is the only way to preserve peace and purity in the church.