Tribute, Spoils, and Rulership (Kitab Al-Kharaj, Wal-Fai' Wal-Imarah)
Dawud :: Book 19 : Hadith 3001
Narrated Abdullah ibn Umar:
Umar said: The Apostle of Allah (peace_be_upon_him) had transaction with the Jews of Khaybar on condition that we should expel them when we wish. If anyone has property (with them), he should take it back, for I am going to expel the Jews. So he expelled them.