In Matthew 18, Jesus is speaking to his disciples, and the passage concerns the authority and responsibility of the Church in dealing with sin, reconciliation, and life within the Christian community. Earlier, in Matthew 16:19, Jesus gives this authority specifically to Peter when he says: “I will give you the keys of the kingdom of heaven. Whatever you bind on earth shall be bound in heaven…”
Then, in Matthew 18:18, that language is extended to the apostolic community. The important point is that the binding and loosing is done on earth by those to whom Christ entrusts the authority, but the authority itself comes from Christ.
Therefore, the Church does not create God’s truth; she receives, guards, interprets, and applies what Christ has entrusted to her.
To “bind” could mean to prohibit, to declare something forbidden, or to impose an obligation. To “loose” could mean to permit, release from an obligation, or declare something lawful. So Jesus is giving his apostles real authority to make judgments concerning the life of God’s people.
This becomes especially visible in the Sacrament of Reconciliation, where Christ’s authority to forgive sins is exercised through the ordained ministry of the Church.
Christ has entrusted his Church with genuine authority to govern, teach, reconcile, and discipline his people, and Christ stands behind the legitimate exercise of that authority. The Church acts in the name of Christ, not in place of Christ.
Jesus’ words about binding and loosing reveal that the Christian faith is not simply a private relationship between an individual and God. Christ entrusted his apostles and, through them, their successors with real authority to teach, govern, reconcile, and discipline his people.