Regard him as one who points out treasure, the wise one who seeing your faults rebukes you. Stay with this sort of sage. For the one who stays with a sage of this sort, things get better, not worse. Let him admonish, instruct, deflect you away from poor manners. To the good, he's endearing; to the bad, he's not.
Panditavagga: The Wise, 76-77, trans Thanissaro Bhikkhu