The Purpose of including the Graves of the Messenger and His two Companions in Al-Masjid An-Nabawi

Question:

It is known that it is not permissible to bury people in mosques, and that praying in a mosque containing a grave is not permissible. What is the purpose of including the graves of the Messenger and His two Companions in Al-Masjid An-Nabawi?

Answer:

It is authentically reported that the Messenger of Allah said:
"The curse of Allah is upon Jews and Christians who turned the graves of their Prophets into praying place".

It is also authentically reported that 'A'ishah mentioned that Umm Salamah, and Umm Habibah, both told the Messenger about a church which they saw in Ethiopia, which contained pictures. The Prophet said:
"Those people, whenever a pious man died among them, they built a praying place on his grave, and posted in them those pictures. Those are the most evil creatures in the sight of Allah.

Jundub bin Abdullah Al-Bajali said: "I heard the Messenger of

Allah saying:
"Allah has taken me for a beloved, as he took Ibrahim for a beloved. Were I to take a friend from my Ummah, I would have taken Abu Bakr for a friend. Beware! Those who came before you used to take the graves of their prophets and pious people for praying places. Beware! Never take graves for mosques, for I forbid you doing so.

Muslim narrated that Jabir, may Allah be pleased with him, reported that the Prophet forbade plastering graves or sitting on them, or building chambers on them." These authentic traditions all signify prohibition in taking graves for mosques. Those who do so are cursed.

These traditions also indicate the prohibition of erecting structures on graves, or building domes upon them, or plastering them. Doing so is considered as means of Shirk, and worshipping the people in those graves to the exclusion of Allah.

This happened in the past and in the present. It is incumbent on Muslims wherever they happen to be to beware of what the Prophet prohibited of constructing on graves, or building mosques and domes on them, plastering them and lighting them, or other things which the Prophet forbade. They should not be deceived by what many people do, for a believer must seek the truth at all times, and uphold it wherever he finds it. The truth can be recognized by the proof from the Book and Sunnah, not by opinions or deeds of men.

Neither the Messenger of Allah, nor his two Companions, may Allah be pleased with them, were buried in the Masjid, rather, they were buried in 'A'ishah's chamber. But when the Masjid was expanded during the reign of Al-Walid bin Abdul-Malik, the chamber was included in the Masjid towards the end of the first century. This is not to be considered as including a grave in the Masjid because neither the Messenger nor his two Companions were transferred into the Masjid. It was only the chamber in which they were buried that was included in the Masjid for the sake of expansion.

Hence, no one should use this as a proof or an argument for the permissibility of erecting structures on graves, or building mosques on them or burying people in them, as indicated by the above mentioned authentic traditions that prohibit doing so. Moreover what Al-Walid did does not constitute an argument to be used against the established Sunnah of the Messenger of Allah. It is Allah Who grants success.
Source:
Fatawa Islamiyah, Vol. 1 Pages 57-58-59