Binding and loosing: The Gospel presents the procedure for dealing with a fellow disciple who sins within the community but has no intention of leaving the Church or ceasing to sin.
The first step is taken privately. Matthew’s Jesus empowers every member of the community to attempt to eliminate sin in the Church by engaging in private correction.
Step two involves taking one or two others along. This is founded on the law (cf Dt 19:15) which states that a person can be accused of a crime only with the support of two or three witnesses.
If the second step fails, the church is convened. This is Matthew’s second of only two uses of the word “church” (the first is in 16:18), which means the local congregation. The local church, in Matthew’s understanding, is the final appeal.
The local church is given the authority to bind and to loose, much as Peter was given the same authority earlier in the Gospel (cf 16:19). Jesus promises that if two persons agree on earth about anything for which they are to pray, it shall be granted to them by the Father. Thus, Matthew endows the local church with power to admit or to exclude people from the community. And the use of this power is ratified by God.