Please read the Scripture passage before the homily.
If you kill someone, you will probably end up in jail. Our criminal laws try to change behavior; they cannot change interior thoughts and intentions. Our laws cannot command love. Jesus, however, does command love and will judge us on how much we have loved.
It works like this. Our actions flow from what is within us. If we allow anger to fester within us, it will give birth to angry words, angry actions, and hurtful behavior. Thus, anger can produce the killing of others. Jesus tells us not even to let anger take hold, lest the anger eventually produce destructive words and actions.
It is important that we worship God. It is more important that we get along with our neighbors. Worshipping God while holding grudges against our neighbor nullifies our worship. Jesus tells us to be reconciled with our opponent so that we can mean what offering our gift to God means.
This is because we can only be at one with God if we are at one with one another. There is a unity of God with all of God’s creation. When we break our union with one another, we break our unity with God. Our reconciliation with one another makes our union with God real.
If our righteousness is only skin-deep and does not reach to the marrow of our bones, then our loyalty to God is superficial, like that of the hypocrites, and we shall not enter the Kingdom of heaven.