Mat 18:15-17 "If your brother sins
[against you], go and show him his fault in private; if
he listens to you, you have won your brother. But if he does not listen to
you, take one or two more with you, so that BY THE MOUTH OF TWO OR THREE
WITNESSES EVERY FACT MAY BE CONFIRMED. 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.
note: [against you] isn't in NASB, but is in Darby, KJV, MKJV and Westcott-Hort
Greek (σέ - Strong's G4571)
but, we have been forgiven much. See Mat 18:22-35 that ends "(35)My heavenly Father will also do the same to you, if each of you does not forgive his brother from your heart."
Luk 17:3-4 "Be on your guard! If your brother sins, rebuke him; and if he repents, forgive him. And if he sins against you seven times a day, and returns to you seven times, saying, 'I repent,' forgive him."
Gal 6:1 Brethren, even if anyone is caught in any trespass, you who are spiritual, restore such a one in a spirit of gentleness; each one looking to yourself, so that you too will not be tempted.
Col 3:16 Let the word of Christ dwell in you richly; in all wisdom teaching and admonishing one another with psalms, hymns, and spiritual songs, singing with grace in your heart to the Lord.
1Ti 5:19-20 Do not receive an accusation against an elder except on the basis of two or three witnesses. Those who continue in sin, rebuke in the presence of all, so that the rest also will be fearful of sinning.
Jam 5:19-20 My brethren, if any among you strays from the truth and one turns him back, let him know that he who turns a sinner from the error of his way will save his soul from death and will cover a multitude of sins.
1Jo 5:16 If anyone sees his brother committing a sin not leading to death, he
shall ask and God will for him give life to those who commit sin not leading to
death. There is a sin leading to death; I do not say that he should make request
for this.