In my Latin-English missal from 1956, the Gospel for today is Matthew 18:15-22:
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.” Then Peter came up and said to him, “Lord, how often shall my brother sin against me, and I forgive him? As many as seven times?” Jesus said to him, “I do not say to you seven times, but seventy times seven.”
Gospel for Tuesday of the Third Week of Lent, The New Roman Missal (Fr. Lasance), 1956.
In the new Missal, the Gospel for today begins with verse 21 and goes through verse 35, in order to associate the idea of forgiving your brother 490 times with the parable of the unforgiving servant (“‘You wicked servant! I forgave you all that debt because you besought me; and should not you have had mercy on your fellow servant, as I had mercy on you?’”). Which makes sense.
But I very much like the combination of confronting your brother with his sin, and having nothing more to do with him if he refuses to listen not only to you, but even to the Church; with forgiving your brother virtually an unlimited number of times. The fact that Jesus addresses these two issues one right after another, is a good underscore to the fact that there is no conflict between the two: Don’t tolerate unrepented sin in the Church, but also be ready to forgive sin at the drop of a hat.
The Church welcomes sinners, not because it tolerates sin, but for the purpose of bringing them to repentance. According to Jesus those who refuse to repent should be to us “as a Gentile and a tax collector”. But those who do repent, like the Prodigal Son should be welcomed back with open arms, not once, not twice, but as many times as they choose to return.