Abu Dawud Book 8, Hadith Number 2721.

Narated By Abdullah ibn Abbas : Yazid ibn Hurmuz said: Najdah wrote to Ibn Abbas asking him about such-and-such, and such-and-such, and he mentioned some things; he (asked) about a slave whether he would get something from the spoils; and he (asked) about women whether they used to go out (on expeditions) along with the Apostle of Allah (PBUH), and whether they would be allotted a share, Ibn Abbas said: Had I not apprehended a folly, I would not have written (a reply) to him. As for the slave, he was given a little of the spoils (as a reward from the booty); as to the women, they would treat the wounded and supply water.