Matthew 18:15–17 (ESV)
If Your Brother Sins Against You
15 “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. 16 But if he does not listen, take one or two others along with you, that every charge may be established by the evidence of two or three witnesses. 17 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.
Matthew 5:22–24 (ESV)
22 But I say to you that everyone who is angry with his brother will be liable to judgment; whoever insults his brother will be liable to the council; and whoever says, ‘You fool!’ will be liable to the hell of fire. 23 So if you are offering your gift at the altar and there remember that your brother has something against you, 24 leave your gift there before the altar and go. First be reconciled to your brother, and then come and offer your gift.
1 Peter 4:8–9 (ESV)
8 Above all, keep loving one another earnestly, since love covers a multitude of sins. 9 Show hospitality to one another without grumbling.