Nafi' narrates from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that Sayyiduna Umar (may Allah be pleased with him) exiled the Jews and the Christians from the land of the Hijaz. When the Messenger of Allah (peace and blessings be upon him) had conquered Khaybar, he wanted to expel the Jews from there, because this land belonged to Allah, the Messenger and the Muslims. When he resolved to expel the Jews, the Jews asked the Prophet (peace and blessings be upon him): If you let us work on the lands, then half of the fruit will be yours. He said: "We will keep you here for as long as we wish." He did keep them, but Sayyiduna Umar (may Allah be pleased with him) exiled them towards the settlements of Tayma' and Ariha.
(b) Musa bin Uqbah (may Allah have mercy on him) says that he (peace and blessings be upon him) said: "We will keep you for as long as we wish."
(c) Usamah bin Zayd (may Allah have mercy on him) narrates from Nafi' (may Allah have mercy on him) that he said: "I will keep you on this for as long as I wish."
(d) Sayyiduna Umar (may Allah be pleased with him) narrates from the Prophet (peace and blessings be upon him): "We will keep you for as long as Allah, the Lord of Might, keeps you."
Imam al-Shafi'i (may Allah have mercy on him) says: If it is asked why every imam after the Messenger of Allah (peace and blessings be upon him) may not say: "I will keep you as long as Allah keeps you," the answer is that the difference between him and the Messenger of Allah (peace and blessings be upon him) is that the command of Allah used to come to the Messenger through revelation, whereas revelation does not come to anyone else.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجزية / 18819