Matthew 18:15-20 has a summary of the traditional process referred to by Christians as a method for addressing and disciplining one another when they sin. The method outlined starts with an individual, one on one approach and then as/if/when escalation occurs it moves the discussion into a more public sphere.
Generally it follows the trajectory of:
1. You see a wrong doing and approach the person privately
2. If, after private consultation, the wrong doing continues, you have another consultation, this time with witnesses
3. If, the matter continues after this, a public action takes place
It is a relatively simple approach that combines privacy, sensitivity and common sense. Many commercial managers and community conflict mediators follow a similar method. For instance a company performance management model follows this almost exactly: An employee will receive a warning, then a meeting with HR, then they are dismissed.
The stated intention is not to shame or discriminate against an individual for lack of conformity. Sadly though many managers have used the “three-strikes” approach to justify removal of unwanted employees and even sadder, many Churches have used the approach to excommunicate unsavory parishioners.
However the aim is a restoration. When restoration fails, the result is that the person is released (or dismissed!) from any organization when they, through their actions, show they no longer want to belong or be identified with their company or, in the case of the Christian, their church.
The summary given in Matthew’s gospel isn’t a detailed process and it doesn’t cover every possible aspect or scenario. The context indicates the inevitability of people straying and stumbling (vv.6-14) and the necessity that forgiving each other plays in identifying each other as co-recipients of God’s forgiveness (vv.21-35). But it doesn’t specify the exact detail, timing and process to follow in every single case.
The emphasis (of vv.18-20 in particular and the broader context of vv.6-35) centres more upon the identification and association of people with the “Father in heaven.” The conduct and association of God’s people, the Church, should reflect and represent the “Father” as though he, himself, is endorsing their actions. If something or someone is not reflecting this ethic, they are dissociating themselves with both the people of the Church and the “Father in heaven.”
For this reason there is a heavy burden for the people of the Church in how they relate to each other as representatives of God. Being harsh and unforgiving presents a view that God is spiteful, hateful and intolerant. Being indiscriminately accommodating presents a God that is unjust and lacking integrity. e.g. Consider the racism promoted in some parts of the USA that were or are sponsored by Churches or the involvement of Church organizations in the Stolen Generations of Australia’s past. Or on the other extreme, the Church choosing not to intervene in domestic violence or prosecute child abusers on the grounds of being “forgiving.”
In any of those examples, a Matthew 18 approach is insufficient. There are plenty of other Bible passages (and indeed civil laws!) that make it clear that no tolerance ought to be given to abusers. The Church ought not let Matthew 18 justify inaction when a woman or child is being hurt. (Or many other instances of “sin” that are too often excused in the name of “forgiveness.”)
The Matthew 18 passage doesn’t go into any detail or make any recommendation of how, where or when (precisely) you “tell it to the church”. The overall context of the chapter is public association, identification and reflection of the ethic of God the Father, and indicates, for the sake of transparency and integrity, the Church is told in an open forum. There may, of course, be instances, where for the sake of sensitivity towards a victim, that an announcement be handled tactfully. However, the church ought not be reluctant exposing an offender for the sake of their own corporate embarrassment.
Especially in the case of violence, abuse, harassment, intimidation and bullying where an offender has previously been warned off. Tell it to the Church and … well … if they don’t listen or act … maybe identifying with God the Father is not their priority. The church is not a kids petting zoo, get out of Dodge.