Jubayr narrates: The Prophet (peace and blessings be upon him) conquered it (Khaybar), and all of it belonged to him, both its crops and its date palms. The Prophet (peace and blessings be upon him) and his Companions had no slaves (to work there), so the Prophet (peace and blessings be upon him) made a settlement with the Jews on the condition that they would take on the work and half of the dates would be theirs, on the condition that "I will let you remain for as long as Allah and His Messenger see fit." It was on that occasion that the Prophet (peace and blessings be upon him) sent Sayyiduna Ibn Rawahah (may Allah be pleased with him) to make the estimate for them, and when he gave the Jews the choice, the Jews took the dates (themselves). Khaybar remained in the hands of the Jews under the settlement of the Prophet (peace and blessings be upon him) until the era of Sayyiduna Umar (may Allah be pleased with him) came, and he expelled them. The Jews said: "Did the Prophet (peace and blessings be upon him) not make a settlement with us on such-and-such terms?" Sayyiduna Umar (may Allah be pleased with him) said: "Indeed he did, on the condition that you would be allowed to remain for as long as Allah and His Messenger saw fit, and now I have seen fit to expel you." So he expelled them, then divided it among the Muslims who had conquered it with the Prophet (peace and blessings be upon him), and he gave nothing of it to anyone who had not been present at its conquest. (The narrator says:) Now its owners are the Muslims; there are no Jews in it. The Prophet (peace and blessings be upon him) ordered the estimation only so that the zakah could be calculated before the fruit was eaten and distributed, and they continued to act upon that.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14018