One-fifth of Booty to the Cause of Allah (Khumus)
كتاب فرض الخمس
Chapter 19: What the Prophet saws used to give to those Muslims whose faith was not so firm
`Umar bin Al-Khattab expelled all the Jews and Christians from the land of Hijaz. Allah's Messenger (ﷺ) after conquering Khaibar, thought of expelling the Jews from the land which, after he conquered it belonged to Allah, Allah's Messenger (ﷺ) and the Muslims. But the Jews requested Allah's Messenger (ﷺ) to leave them there on the condition that they would do the labor and get half of the fruits (the land would yield). Allah's Messenger (ﷺ) said, "We shall keep you on these terms as long as we wish." Thus they stayed till the time of `Umar's Caliphate when he expelled them to Taima and Ariha.
Chapter 20: The food gained as war booty in the battlefield
While we were besieging the fort of Khaibar, a person threw a leather container containing fat, and I ran to take it, but when I turned I saw the Prophet (standing behind), so I felt embarrassed in front of him.
In our holy battles, we used to get honey and grapes, as war booty which we would eat and would not store.
We were afflicted with hunger during the besiege of Khaibar, and when it was the day of (the battle of) Khaibar, we slaughtered the donkeys and when the pots got boiling (with their meat). Allah's Apostle made an announcement that all the pots should be upset and that nobody should eat anything of the meat of the donkeys. We thought that the Prophet (ﷺ) prohibited that because the Khumus had not been taken out of the booty (i.e. donkeys); other people said, "He prohibited eating them for ever." The sub-narrator added, "I asked Sa`id bin Jubair who said, 'He has made the eating of donkeys' meat illegal for ever.")