The Twenty-third Sunday in Ordinary Time [A]

First Reading Ezekiel 33:7-9
Second Reading Romans 13:8-10
Gospel Matthew 18:15-20

Oh, that today you would hear his voice: "Harden not your hearts as at Meribah…."

Today's Responsorial Psalm comes from Psalm 95. It's the last section of today's Responsorial that ties most directly to the rest of this Sunday's scriptures. The refrain of today's Responsorial comes from this section, and is a paraphrase of Psalm 95:7-8: "If today you hear His voice, harden not your hearts."
One notable feature of this sentence is that it speaks in the plural. Its command is to "harden not your hearts", not "your heart". This is a "community psalm", to use a modern phrase. As so many of the psalms make clear, they were composed for liturgical worship, which by its nature is communal rather than individualistic. This is good to remember when we as Christians are tempted to reduce our faith to being simply between "me and Jesus". Just as in Jesus both the divine nature and a human nature fully dwell, so living one's faith in Jesus means fully loving God, and fully loving one's neighbor. As soon as we prefer one of these to the other, our faith is no longer focused in Christ.
This leads us to ask why Psalm 95 exhorts us to harden not our hearts when we hear the Lord's voice. What about the Lord's voice could tempt us to do so? The answer is two-fold. The first is His command to love Him with faith. During the Exodus, God's people demanded signs from God of His power. This is what Psalm 95 is referring to directly. In our own lives each of us sins when we lose faith in God's providential love, in which all things—even sin and evil—work together for good, in the words of Saint Paul.
We are also tempted to harden our hearts when the Lord's voice calls us to love our neighbor, especially in the form of forgiveness. Here the Responsorial Psalm ties together this Sunday's other scriptures. The Second Reading explains God's command that we love our neighbor. The First Reading and Gospel passage focus on God's command to love our neighbor by offering fraternal correction.
Offering fraternal correction can easily lead to the hardening of one's heart. It can lead to cynicism and self-righteousness, or can be thwarted by our fear of the other's response. But these threats to our spiritual peace don't excuse us from the Lord's command. One of the helpful points from today's Gospel passage is that Jesus situates our need to offer fraternal correction within the setting of the Church.
In only two passages in all the four Gospel accounts does the word "church" appear. In fact, these two passages are very close to each other: in chapters 16 and 18 of Matthew. In both, Jesus gives His Church the power "to bind and to loose". In today's passage, Jesus explains that He's speaking about that power in the context of a brother's sin.
Jesus is very clear about the steps that need to be taken. They begin by speaking with the sinner himself. A sinner is not tried, convicted, or sentenced in absentia, because it's the sinner's welfare that is at stake as much as the welfare of the one who is sinned against. In our modern throw-away culture, we may not wish to love the criminal, but only the victim. Jesus is calling us to love both, as He did on His Cross.
Here's a practical suggestion for the next time you need to offer fraternal correction. If you struggle, whether because your heart is fearful or callous, to offer fraternal correction, go first to God in the Sacrament of Confession. Admit there your own sinfulness to Him who is the Father of both you and the one whom you must correct. Being on the receiving end of divine mercy will help form you into a bearer of mercy, and help you approach your brother with the same love for Him that Jesus showed him on the Cross. This is the love that effects communion within the Church, and that makes Jesus present in the midst of us.