Maqsim bin Bajra مقسم بن بجرة · Commercial Transactions (Kitab Al-Buyu)

The Prophet (ﷺ) handed over the Jews of Khaibar the palm trees and the land of Khaibar on condition that they should employ what belonged to them in working on them, and that he should have half of the fruits.

He said: He assessed, and after the words of kull safara' wa baida', he said: that is, gold and silver will belong to him.