Surah Fusilat (The Verses Prefectly Explained), Verse 34

وَلَا تَسْتَوِی الْحَسَنَةُ وَلَا السَّیِّئَةُ اِدْفَعْ بِالَّتِیْ هِیَ اَحْسَنُ فَاِذَا الَّذِیْ بَیْنَكَ وَبَیْنَهٗ عَدَاوَةٌ كَاَنَّهٗ وَلِیٌّ حَمِیْمٌ ۟

Wa laa tastawil hasanatu wa las saiyi'ah; idfa' billatee hiya ahsanu fa'izal lazee bainaka wa bainahoo 'adaawatun ka'annahoo waliyun hameem

“Nor can goodness and Evil be equal. Repel (Evil) with what is better: Then will he between whom and thee was hatred become as it were thy friend and intimate!”

Quran 41:34 (Yusuf Ali Translation)