Najdah wrote to Ibn Abbas (may Allah be pleased with them both) asking him about the orphan, when his orphanhood ends; about killing children; whether a slave has any share of the fay' (spoils); and for whom the khums (one-fifth) is. Ibn Abbas (may Allah be pleased with them both) said: Were it not for fear that he would commit some great folly, I would not write to him. Then he wrote to him: As for the orphan, when he reaches puberty and sound judgement is perceived in him, his orphanhood has ended. As for the children, if you know about them what al-Khidr (peace be upon him) knew, then so be it; otherwise, do not kill them. As for the slave, he used to be given something from the spoils. As for the women, they used to treat the wounded and give water. As for the khums, we hold that it is ours, but our people hold that it is not ours.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10785