Musnad Ahmad 1153:878

'Affan narrated to us, he said: Abu 'Awanah narrated to us, he said: Hilal ibn Abi Humayd narrated to us, from 'Urwah ibn al-Zubayr, from 'Aishah, she said: The Messenger of Allah (may Allah bless him and grant him peace) said during his illness from which he did not recover: "May Allah curse the Jews and the Christians; they took the graves of their prophets as places of worship." She said: I said: "And were it not for that, his grave would have been made prominent, except that he feared it would be taken as a place of worship."