#1 Matthew 18:15 If your brother sins against you, go and show him his fault, just between the two of you. If he listens to you, you have won your brother over.
#2 Romans 12:19-21 Do not take revenge, my friends, but leave room for God's wrath, for it is written: “It is mine to avenge; I will repay,” says the Lord. On the contrary: “If your enemy is hungry, feed him; if he is thirsty, give him something to drink. In doing this, you will heap burning coals on his head.” Do not be overcome by evil, but overcome evil with good.
#3 2 Corinthians 2:5-8 If anyone has caused grief, he has not so much grieved me as he has grieved all of you to some extent—not to put it too severely. The punishment inflicted on him by the majority is sufficient. Now instead, you ought to forgive and comfort him, so that he will not be overwhelmed by excessive sorrow. I urge you, therefore, to reaffirm your love for him.