Nahj al-Balagha Hadith n. 314

Selections from The Sayings and Preaching of Amir al-Muminin Ali ibn Abi Talib (Peace Be Upon Him) Including His Replies to Questions and Maxims Expressed for Various Purposes.
Translated by Sayyid Ali Reza

وَقَالَ (عليه ‏السلام):

Amir al-mu'minin, peace be upon him, said:

رُدُّوا الْحَجَرَمِنْ حَيْثُ جَاءَ،

Throw a stone in return from where one comes to you

فَإِنَّ الشَّرَّ لاَ يَدْفَعُهُ إِلاَّالشَّرُّ.

because evil can be met only with evil.