It is narrated from Lady Aisha and Sayyiduna Ibn Abbas, may Allah be pleased with them, both said: When the Messenger of Allah, peace and blessings be upon him, became ill (i.e., in his final illness), he would cover his blessed face with a sheet, and when he felt short of breath, he would uncover his mouth and in that state would say: "May Allah's curse be upon the Jews and Christians; they took the graves of their prophets as places of worship." The Prophet, peace and blessings be upon him, was warning against doing as they did.