“Verily, you (O Muhammad) will die, and verily, they (too) will die” [al-Zumar 39:30]
“And We granted not to any human being immortality before you (O Muhammad); then if you die, would they live forever?” [al-Anbiyaa’ 21:34]
The Messenger (peace and blessings of Allaah be upon him) died and was buried in his grave, hence al-Siddeeq Abu Bakr (may Allaah be pleased with him) said: “Whoever used to worship Muhammad, Muhammad has died, but whoever used to worship Allaah, Allaah is alive and will never die.”
The fact that the Prophet (peace and blessings of Allaah be upon him) was a witness, a bringer of glad tidings and a warner, and that he will be a witness on the Day of Resurrection, does not mean that he is present among all nations, or that he (peace and blessings of Allaah be upon him) will remain alive until the Day of Resurrection, or that he sees and witnesses whilst he is in his grave. Witnessing does not only mean seeing. Rather he will testify against the nations by means of what Allaah tells him, for he does not know the unseen. Allaah says (interpretation of the meaning):
“… and If I had the knowledge of the Ghaib (Unseen), I should have secured for myself an abundance of wealth…”[al-A’raaf 7:188]
The Prophet (peace and blessings of Allaah be upon him) does not have the ability to be present in numerous places; he is in only one place, which is his grave, and this is according to the consensus of the Muslims.