Nahjul Balagha Instruction 14

Given to the army before the encounter with the enemy at Siffin

Do not fight them unless they start fighting, because by Allah’s grace, you are in the right and to leave them till they start fighting will be another point from your side against them. If by Allah’s will, the enemy is defeated then do not kill the runner away, nor strike a helpless person, or finish off the wounded, and do not inflict pain on women even though they may attack your honour with filthy words and abuse your officers, because they are weak in character, mind and intelligence. We have been ordered to desist from them although they may be unbelievers. Even in pre-Islamic period if a man struck a woman with a stone or a stick he was rebuked along with his latter after him.