It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) fought the people of Khaybar until he confined them to their fortress and took control of the land and the orchards. They said: "O Muhammad, let us stay here; we will look after these orchards." Neither the Prophet (peace and blessings be upon him) nor the Companions (may Allah be pleased with them) had servants who could stay there. So the Prophet (peace and blessings be upon him) gave them Khaybar on the condition that they would give half of the fruit, grain or whatever else there was. Sayyiduna Abdullah bin Rawahah (may Allah be pleased with him) would go to them every year, make the khars (estimate), and then hold them liable for half. One year they complained to the Messenger of Allah (peace and blessings be upon him) about the severity of the estimate of Sayyiduna Abdullah bin Rawahah (may Allah be pleased with him), and they wanted to bribe him. He (Abdullah bin Rawahah) said: "O enemies of Allah! Would you feed me what is unlawful? I have come to you from the person most beloved to me, and you are more hateful to me than your number in apes and swine; yet my hatred of you and my love for him will not lead me to be unjust to you." Then they said: "By this justice the heavens and the earth stand."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المساقاة / 11626