Sin, of whatever form, is not to be tolerated within the disciple community, but is to be dealt with when it is noticed. But what is at stake is winning over the brother or sisters. The pastoral purpose of the approach is underlined by the verb “win,” which shows that the concern is not mainly with the safety and/or reputation of the whole community but with the spiritual welfare of the individual. “Win” suggests that the person was in danger of being lost, and has now been regained; it reflects the preceding image of the shepherd’s delight in getting his sheep back (v.12).
From our own experience as people we know that such situations must be dealt with sensitively and with a minimum of publicity. The principle set out in these verses is of minimum exposure, other people being brought in only when the more private approach has failed. The ideal solution is “you and him alone.” But it is to be explicit and robust in the telling of the sin witnessed: elenchō is not a gentle verb. It is not easy to capture the force of elenchō here in a single English word. It includes the related ideas of reprimand, of bringing the wrong to light, of trying to bring the person to recognize that they are in the wrong, and of correcting them.
Elenchō assumes, as this whole passage assumes, that the person raising the issue is in the right and that the behavior being criticized is self-evidently wrong. In practice matters are not always so straightforward, and it behooves the person taking the initiative to make sure that the “sin” is not simply a matter of personal preference; the eventual involvement of the “one or two” and then of the church should minimize that danger.
Sin and Listening. The hoped for response is akouo, — that the sinner might “listen,” but this word can extend beyond what the ears do, to what the mind does, “understand, comprehend.” Twice in v. 17 a form of this word is used, parakouo. Our NAB version translates it “refuses to listen,” which grows out of its more literal meanings: “to mis-hear” or “to misinterpret.” A good bit of advice is that if we want people to akouo to us in such situations, the words we say must be true, necessary, and helpful – so that they more than just hear the words, but open hearts and minds to receive the word.
Brian Stoffregen notes that in Scott Peck’s book, People of the Lie: The Hope for Healing Human Evil  Peck writes it “is not their sins per se that characterize evil people, rather it is the subtlety and persistence and consistency of their sins. This is because the central defect of the evil is not the sin but the refusal to acknowledge it.” But if in the encounter instead of akouo we experience parakouo, we have no option – for the sake of the sinner and the community – but to begin to consider a more robust response. According to Peck, committing sins is not the same thing as being evil. We all commit sins. However, the sinners who won’t listen to the one, or the two or three, or to the church, need to be removed not because they are sinners, but because they are evil — unwilling to listen to the truth about their sins — attacking others instead of facing their own failures. In this case, it is healthier for the body to remove the evil (cancerous) part that would destroy the whole, than to try to keep the “family” together.
Why Witnesses? The initial one-on-one approach has not been successful, so more drastic action is needed. Again there is no suggestion that the “one or two others” hold any position of leadership, and no indication of how they should be selected. Why take along one or two others after the first non-listening response?
First of all, Jewish law required two or three witness to uphold a complaint (Dt 19:15). Secondly, the witnesses need to be present, because they may conclude that the confronter may be in the wrong. The accusations against a fellow member may be way off-base. The one or two then may become the confronters against the original accuser. A third reason might be deduced from the last line in our text: “For where two or three are gathered in my name, I am there among them.” We don’t often connect these two verses — as well as v. 19: “if two of you agree on earth about anything for which you are to pray, it shall be granted to them by my heavenly Father.” Note that the word (pragma) translated “thing” in “anything,” can have the more specific meaning of a legal case, litigation (see 1 Cor 6:1 where it is translated “grievance,” but refers to a legal complaint). Malina and Rohrbaugh suggest the translation: “For where two or three ‘convene to hear a case’ in Jesus’ name, Jesus is there as well.” [p. 119]
Matthew 18:16 listen: akouō listen or hear, but primarily “come to know.”