Musnad Abu Ya'la al-Mawsili 8:3

Abu Khaythama narrated to us, Yahya ibn Sa'id al-Qattan narrated to us, from Ibrahim ibn Maymun, who said: Sa'd ibn Samura ibn Jundub narrated to me, from his father, from Abu Ubaydah ibn al-Jarrah, who said: The last thing the Messenger of Allah, peace and blessings of Allah be upon him, spoke was: "Expel the Jews of the Hijaz and the people of Najran from the Arabian Peninsula, and know that the worst of people are those who took their graves as places of worship."