Qur'an, Surah 41:34-36
The good deed and the evil deed are not alike. Repel the evil deed with one which is better, then lo! he, between whom and you was enmity will become as though he was a bosom friend. But none is granted it save those who are patiently enduring and none is granted it save the owner of great happiness. And if a whisper from satan reach you, then seek refuge in Allah. Lo! He is the Hearer, the Knower.