Najdah wrote to Ibn Abbas (may Allah be pleased with them both) asking him about five matters. Ibn Abbas (may Allah be pleased with them both) said: Were it not that I would be concealing knowledge, I would not write to him. Najdah wrote to him: To proceed: tell me, did the Messenger of Allah (peace and blessings be upon him) take women with him on military expeditions? Did he (peace and blessings be upon him) fix a share of the spoils for them? Did he (peace and blessings be upon him) kill children? When does the orphanhood of an orphan end? And for whom is the khums (one-fifth)? Ibn Abbas (may Allah be pleased with them both) wrote to him: You wrote asking me whether the Messenger of Allah (peace and blessings be upon him) took women with him on military expeditions. Yes, he (peace and blessings be upon him) used to take them, and they would treat the wounded and be given something from the spoils, but a share was not formally fixed for them. And the Messenger of Allah (peace and blessings be upon him) did not kill children. And you wrote asking when the orphanhood of an orphan ends. By my life, a man's beard may grow and he may still be weak in taking for himself and weak in giving from it; so when he takes for himself in the way sensible people take, his orphanhood has ended. And you asked me about the khums, for whom it is. We say: It is ours, but our people refused us that.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10787