Imam Malik's Muwatta, Chapter: Jihad

Yahya related to me from Malik from Abu'z-Zinad that Said ibn al-Musayyab said, "People used to be given bonuses from the Khumus." Malik said, "That is the best of what I have heard on the matter." Malik was asked about bonuses and whether they were taken from the first of the spoils, and he said, "That is only decided according to the ijtihad of the Imam. We do not have a known reliable command about that other than it is up to the ijtihad of the Sultan. I have not heard that the Messenger of Allah, may Allah bless him and grant him peace, gave bonuses in all his raids. I have only heard that he gave bonuses in one of them, namely the day of Hunayn. It depends on the ijtihad of the Imam whether they are taken from the first of the spoils or what is after it."