हनते को हनिए पाप दोष न गनिए |

Proverb (in Latin script): 
Hante Ko Haniye Pap Dosh Na Ganiye.
Meaning: 
यदि कोई व्यक्ति बिना कारण आपको या दूसरे को मारता है, तो उसको मारना पाप नहीं है |
Meaning (in English): 
If a person hurts you or anyone else without reason, it is not a sin to hurt him back.
Equivalent English Proverb: 

To kill an enemy is no sin.