Gospel (Mt 18:15-20)
If your brother sins against you, go and tell him his fault, between you and him alone. If he listens to you, you have gained your brother. But if he does not listen, take one or two others along with you, that every word may be confirmed by the evidence of two or three witnesses. If he refuses to listen to them, tell it to the church; and if he refuses to listen even to the church, let him be to you as a Gentile and a tax collector.
Truly, I say to you, whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven. Again I say to you, if two of you agree on earth about anything they ask, it will be done for them by my Father in heaven. For where two or three are gathered in my name, there am I in the midst of them.
The Gospel for this Sunday is made up of three sayings of Jesus that give us norms for important aspects of the Church’s future: fraternal correction among the faithful, the power to bind and loose given to the Apostles and their successors, and the effectiveness of prayer in common.
Jesus’ message does not make people sinless; but it does ask us to love one another despite our defects and mistakes. A clear demonstration of this love is the mutual help given through forgiveness and correction. With this first teaching, Jesus invites each of us to be a merciful judge who shows understanding towards anyone who has harmed us in any way. As Saint Josemaria said, “To practice fraternal correction—which is so deeply rooted in the Gospel—is a proof of supernatural trust and affection. Be thankful for it when you receive it, and don’t neglect to practise it with those around you.” Pope Francis stressed that fraternal correction prevents “that bitterness of heart which brings anger and resentment, and which leads us to insult and aggression. It’s terrible to see an insult or taunt issue from the mouth of a Christian … To insult is not Christian.”
The Fathers of the Church saw fraternal correction as a noble act of friendship, and drew practical consequences based on Jesus’ words. For example, Saint Augustine admonished the faithful: “we ought, then, to correct our brother out of love; not with the wish to do him harm, but with the affectionate intention of achieving his improvement. If we do it in this way, we will fulfill the precept very well.
Regarding Jesus’ second saying (v. 18), the Catechism of the Catholic Church teaches: “The words bind and loose mean: whomever you exclude from your communion, will be excluded from communion with God; whomever you receive anew into your communion, God will welcome back into his. Reconciliation with the Church is inseparable from reconciliation with God” (no. 1445). After speaking about reconciliation between brothers, Jesus gives his Apostles the power to reconcile the faithful with the Church. This power is ordinarily exercised by confessing one’s sins to the confessor, who has received this power from the bishop, successor of the Apostles.
Finally, Jesus refers to prayer in common. “Another fruit of love in the community is prayer in common,” Benedict XVI said. “Personal prayer is of course important, indeed indispensable, but the Lord guarantees his presence to the community—even if it is very small—that is united and in agreement, because this reflects the very reality of the Triune God, perfect communion of love.” When we pray in union with others, we not only move God to grant us what we ask for. We also receive the gift of the presence of God himself among us, which is the principal gift we can and should beseech him for.
As the Magisterium explains: “Christ is always present in His Church, especially in her liturgical celebrations. He is present in the sacrifice of the Mass, not only in the person of His minister, the same now offering, through the ministry of priests, who formerly offered himself on the cross, but especially under the Eucharistic species. By His power He is present in the sacraments, so that when a man baptizes it is really Christ Himself who baptizes. He is present in His word, since it is He Himself who speaks when the Holy Scriptures are read in the Church. He is present, lastly, when the Church prays and sings, for He promised: ‘Where two or three are gathered together in my name, there am I in the midst of them’ (Mt 18:20).”
 Saint Josemaria, The Forge, no. 566.
 Pope Francis, Angelus, 7 September 2014.
 Saint Augustine, Sermon 82.
 Pope Benedict XVI, Angelus, 4 September 2011.
 Vatican II, Sacrosanctum Concilium, no. 7.