This verse sets the stage for the instructions on tough love this passage gives because it reminds us right off the bat that a right motivation behind reproof must be brotherly love. Jesus doesn’t command us to correct everybody who sins against us. However when we see a brother (in Christ)–one who shares the Spirit given desire for holiness–walking in sin, you should love him by guiding him in his walk toward holiness, with a gentle, humble, loving word. So remember, Jesus’ instruction on correction are given to us to be practiced out of a heart of love for one another.
In reading “sins against you” our selfishness may automatically translate the rest of the passage to instruct a proper response to an offense. However Jesus’ message is much deeper than the proper response to an offense. His message is forgiveness and his instruction is to respond out of love. Not out of an offense, although the offense may be true.
If your brother sins against you, tell him. We should already know this because of Leviticus 9:17 telling us that rather than stewing over bitterness which causes us to sin, we should talk to each other about our concerns. Tell him. Tell him. How often do we skip the first step of resolution given to us by God the Father in Leviticus 9:17, and then again by God the Son in Matthew 18:15. Why? In my life I have held onto my bitterness as if it was comfort, and indeed it was. It comforted my pride. My sinful nature that elevated myself above others was consoled by my bitterness that recited the failure of others. When we are not walking in the Spirit, it is in our nature to stew, and gossip rather than share our hurt with our offending brother. But when we do walk in the Spirit, we hurt not for ourselves when offended, but for our brother the offender! Because he is straying from his hearts true desire for the glory of God to be manifest in his life.
The example we have of gracious and gentle reproof is the example of Jesus Christ. In the glow of his righteousness our sins are brought to light. But he does not expose our sin to condemn us or lay guilt upon us, but so that we might find holiness and grace, being set free to enjoy the life we were created for (John 3:17).
So when we receive offense from a brother, we are to be like our true brother Jesus Christ. We are to look to our offending brother with love, absorbing his offense like a sponge, letting its hurtful energy dissipate in us, softened by the grace of Christ’s example, and in humility (because we have certainly not lived without offending others, most of all our perfect Father and Saviour God.