Sutra in Forty-Two Sections

Section 5
Reducing the Severity of Offenses
The Buddha said, "If a person has many offenses and does not repent of them, but cuts off all thought of repentance, the offenses will engulf him, just as water returning to the sea will gradually become deeper and wider. If a person has offenses and, realizing they are wrong, reforms and does good, the offenses will dissolve by themselves, just as a sick person who begins to perspire will gradually be cured. "

Section 6
Tolerating Evil-doers and Avoiding Hatred
The Buddha said, "When an evil person hears about your goodness and intentionally comes to cause trouble, you should restrain yourself and not become angry or blame him. Then the one who has come to do evil will do evil to himself. "

Section 7
Evil Returns to the Doer
The Buddha said, "There was a person who, upon hearing that I observe the Way and practice great humane kindness, intentionally came to berate me. I was silent and did not reply. When he finished abusing me, I asked, 'If you are courteous to people and they do not accept your courtesy, the courtesy returns to you, does it not? '

- http://www.fodian.net/English/42sectionssutra.htm
- wong chee tat :)