“Take heed to yourselves: If thy brother trespass against thee, rebuke him; and if he repent, forgive him.”
Luke 17:3 — Greek Interlinear
Church Fathers on Luke 17:3
After the parable of the rich man who is tormented in punishment, Christ added a commandment to give forgiveness to those who turn themselves from their trespasses, lest any one through despair should not be reclaimed from his fault; and hence it is said, Take heed to yourselves.
As if He says, Offenses must needs come; but it does not follow that you must perish, if only you be on your guard: as it need not that the sheep should perish when the wolf comes, if the shepherd is watching. And since there are great varieties of offenders, (for some are incurable, some are curable,) He therefore adds, If your brother trespass against you, rebuke him.
But we must mark, that He does not bid us forgive every one who sins, but him only who repents of his sins. For by taking this course we may avoid offenses, hurting no one, correcting the sinner with a righteous zeal, extending the bowels of mercy to the penitent.