Sahih Muslim Book 19, Hadith Number 4460.

Chapter : Women participants in jihid to be given a prize but not a regular share in the booty, and prohibition to kill children of the enemy.

It has been narrated on the authority of Yazid b. Hurmuz who said: Najda wrote to Ibn Abbas. I was sitting in the company of Ibn ‘Abbas when he read his letter and wrote its reply. Ibn Abbas said: Were it not for preventing him from falling into wickedness. I would not have replied to his letter, may he never be joyful. He wrote in reply to him referring to the share of the close relatives (of the Holy Prophet) (from the booty) whom God has mentioned. (I have to tell you that) we thought we were the close relatives of the Messenger of Allah (may peace be upon him), but our people have refused to recognise us as such. You have asked about the orphan as to when his orphan-hood comes to an end. (I have to say that) when he reaches the age of marriage, attains maturity of mind, and his property is returned to him, then he is no longer an orphan. You have inquired whether the Messenger of Allah (may peace be upon him) used to kill anyone from the children of the polytheists in the war. (You should know that) the Messenger of Allah (may peace be upon him) used not to kill any one of their children, and you (too) should not kill any one of them, except when you knew about them what Khadir had known about the boy whom he killed. And you have inquired whether there is a fixed share of the booty for women and slaves when they participate in a battle. (I have to tell you that) there is no fixed share for them except that they will be given some reward from the spoils of war.