Adam Clarke on Matthew 18:15

If thy brother - Any who is a member of the same religious society, sin against thee, 1. Go and reprove him alone, - it may be in person; if that cannot be so well done, by thy messenger, or in writing, (which in many cases is likely to be the most effectual). Observe, our Lord gives no liberty to omit this, or to exchange it for either of the following steps. If this do not succeed,