Jesus’ practices for reconciliation and discipline ought to be understood as pertaining to very serious matters of notorious sin where the health of the community is at stake, and it is not to be understood as a license for the church to resolve any conflict without the involvement of civil authorities when appropriate.
Still, membership in the community of faith is a matter of eternal significance, for "whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven" (v. 18). Jesus is speaking about keeping earthly order within the heavenly community of faith. His process is one that avoids escalation, seeking to correct and reconcile without shaming or embarrassing the person in error, and seeking the offender’s repentance and return. The final measure of excommunication is to be taken only if the person persists in sinful behavior even against the will of the entire local community. Such a level of willful recalcitrance makes exclusion the only available step to remove the threat of a malign influence influencing others in the community to sin.
The preacher will need to walk a narrow way between those in the audience who are over eager to exercise what they suppose to be spiritual discipline and those who are repulsed by the very notion that their local church community claims any authority over their lives at all. The preacher would do well, regarding verse 17, to point out that Jesus pursued tax collectors and Gentiles with genuine love in order to invite them into his kingdom, but the price of entry was not remaining tax collectors, nor living like Gentiles.
