Sahih Muslim Book 4, Hadith Number 1079.

Chapter : Change of Qibla from Bait-u’l-Manqdis to Ka’ba.

‘Aisha reported: The Messenger of Allah (may peace be upon him) said during his illness from which he never recovered: Allah cursed the Jews and the Christians that they took the graves of their prophets as mosques. She (‘Aisha) reported: Had it not been so, his (Prophet’s) grave would have been in an open place, but it could not be due to the fear that it may not be taken as a mosque.