Musannaf Ibn Abi Shaybah 7755 — Sending blessings at the grave

It is narrated from Sayyidah Aishah (may Allah be pleased with her) that the Prophet (peace and blessings be upon him) said during his final illness: "Allah Almighty cursed the Jews and the Christians, because they took the graves of their prophets as places of prostration." Sayyidah Aishah (may Allah be pleased with her) said: Had there not been the fear that the blessed grave of the Prophet (peace and blessings be upon him) would be taken as a place of prostration, his blessed grave would have been made prominent and conspicuous.