Mukhtasar Bukhari

Umm al-Mu'mineen Aisha Siddiqa (may Allah be pleased with her) and Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) say that when the Messenger of Allah (peace and blessings be upon him) was overtaken by (the illness of death), he began to place his cloak over his face. Then, when he felt heat from it, he would remove it from his face. Then, in this state, he said: "May Allah curse the Jews and the Christians, for they took the graves of their prophets as places of worship." He (peace and blessings be upon him) was warning against their actions.