In the name of allah our creator , god of Abraham , Moses , Jacob , Jesus and all prophets

Fight in the way of Allah those who fight you but do not transgress. Indeed. Allah does not like transgressors

The holy Quran 2:190

Narrated Buraidah:

from his father who said: "Whenever the Messenger of Allah (
) dispatched a commander of an army he would exhort him personally; that he should have Taqwa of Allah, and regarding those of the Muslims who are with him; that he should be good to them. He would say: 'Fight in the Name of Allah and in Allah's curse. Fight those who disbelieve in Allah and fight, do not be treacherous, nor mutilate, nor kill a child."

Reference : Jami at-Tirmidhi
Chapter : What Has Been Related About The Prohibition of Mutilation
: Autentic Hadith