Yazid bin Hurmuz says that Najdah wrote to Sayyiduna Ibn Abbas (may Allah be pleased with them both) asking him about certain things, and he mentioned his question and the answer of Sayyiduna Ibn Abbas (may Allah be pleased with them both). Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: "You have asked about the woman and the slave, whether they have a share when they take part in the fighting. They have no fixed share, but they are to be given something as a gratuity from the spoils of the enemy."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الفيء والغنيمة / 12912
Yazid bin Hurmuz related the story, that Ibn Abbas (may Allah be pleased with them both) wrote to him: You have asked me whether women used to go on military expeditions with the Messenger of Allah (peace and blessings be upon him). Indeed, they used to take part in the expeditions; they would treat the sick and would be given a gratuity from the spoils, but there was no fixed share for them.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الفيء والغنيمة / 12913
Umayr (may Allah be pleased with him), the slave of Abu al-Lahm, related: I was present at Khaybar while I was a slave. I said: O Messenger of Allah (peace and blessings be upon him)! Give me a share as well. So he (peace and blessings be upon him) gave me a sword. He (peace and blessings be upon him) said: "Hang this sword on yourself," and he (peace and blessings be upon him) gave me some odds and ends of goods, but he did not give me a share.
Muslim recorded another hadith on zakah with this chain, and this text too is sahih (authentic) on his condition.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الفيء والغنيمة / 12914
Hashraj bin Ziyad narrates from his grandmother (may Allah be pleased with her) that she went out with the Messenger of Allah (peace and blessings be upon him) on the expedition of Khaybar. She was the sixth of six women. The Messenger of Allah (peace and blessings be upon him) learned of it, and he (peace and blessings be upon him) sent word to us to be called. When we came to him (peace and blessings be upon him), we saw anger in him (peace and blessings be upon him). He (peace and blessings be upon him) said: "With whom did you go out, and with whose permission did you go out?" We said: O Messenger of Allah! We came out to spin yarn and help with it in the path of Allah; we have medicine for the wounded, we will hand over the arrows and give sawiq to drink. He (peace and blessings be upon him) said: "Stay." Then, when Allah Almighty granted the conquest of Khaybar, he (peace and blessings be upon him) gave us a share just as he gave the men. The narrator says: I asked my grandmother: O grandmother! What was it? She said: Dates.
The Shaykh said: In this report, what he (peace and blessings be upon him) gave them was by way of a gratuity; he did not allot a share for them.
It is also narrated from Makhul and others that shares were allotted to them at Khaybar, but that is munqati' (broken chain); no proof is established by it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الفيء والغنيمة / 12915