Sa'id bin al-Musayyib (may Allah have mercy on him) says that when Khaybar was conquered, the Messenger of Allah (peace and blessings be upon him) said to the Jews of Khaybar: "I will let you remain as long as Allah lets you remain, on the condition that the dates are shared between us and you." He says: Then the Messenger of Allah (peace and blessings be upon him) used to send Abdullah bin Rawahah (may Allah be pleased with him), who would estimate the yield for them and then say: "If you wish, it is yours, and if you wish, it is mine." And they would take it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7437