Musnad Ahmad 11:2

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