Luke 17:1-4
7 Jesus said to his disciples: "Things that cause people to sin are bound to come, but woe to that person through whom they come. 2 It would be better for him to be thrown into the sea with a millstone tied around his neck than for him to cause one of these little ones to sin. 3 So watch yourselves.
"If your brother sins, rebuke him, and if he repents, forgive him. 4 If he sins against you seven times in a day, and seven times comes back to you and says, 'I repent,' forgive him."
NIV