It is well known that praying in mosques that contain graves is not part of the religion of Islam

The questioner: They argue, Professor, regarding the grave of the Prophet (may Allah’s prayer and peace be upon him), and Muslims pray facing it; we need clarification, Shaykh?

The Shaykh: This question is also explained in "Tadhkir al-Sajid" (Warning to the One Who Prostrates).

The questioner: We want to record about it...

The Shaykh: In brief, yes.

The questioner: With some...

The Shaykh: You take the book, read the chapter, and record it, as for...

The questioner: No...

Another questioner: ...the speech... May Allah be pleased with you.

The Shaykh: As for the question; in brief: we cannot compose a new work now, as the work already exists.

The questioner: So they will hear this recording and say it is the grave of the Messenger, so it will be attached to the rest.

Another questioner : ... .

The questioner: ...the speech is attached to the rest.

The Shaykh: Praying in the Messenger’s Mosque is an exception; because it has a special virtue over all other mosques except the Mosque of Makkah. It was reported in "Sahih Muslim" and others from the hadith of Abu Hurayrah (may Allah be pleased with him), who said: The Messenger of Allah (peace and blessings be upon him and his family) said: . This virtue was spoken of by the Messenger of Allah (peace and blessings be upon him and his family) in his own mosque, and this is a virtue that will not be abrogated for all time; because no one has the authority to abrogate a ruling from the rulings of Islam; whether that is established in the Sunnah or in the Qur'an. And as long as that is the case, this ruling does not change due to what occurred in the Messenger’s Mosque (peace and blessings be upon him and his family) after his passing by about a hundred years; whether in terms of bringing the grave into the mosque, or in terms of decorating the mosque, or in terms of bringing in the mihrab which did not exist in his time (peace be upon him), or other matters that were introduced into al-Masjid al-Nabawi; these matters that were innovated do not abrogate this eternal ruling; which is his saying (peace be upon him): .
So praying in the Messenger’s Mosque (peace be upon him) is most like the greeting of the mosque prayer, or the sunnah of wudu, or similar to those voluntary prayers that are known among scholars as "those with causes." The stronger opinion regarding these voluntary prayers with causes is that they are valid and prescribed in the times of dislike. And in the times of dislike, establishing the prayer is not valid; because he (peace be upon him) said: . Meaning: these prayers are invalid. But the voluntary prayers with causes are not invalid; rather, they are valid even if prayed in the times from which one is prohibited. Similarly, the prayers that a Muslim prays in al-Masjid al-Nabawi are valid, whereas if he prays them in other mosques built over graves, they are not valid; because this prayer in al-Masjid al-Nabawi has the virtue of a thousand prayers, while those prayers that are prayed in other mosques do not have any virtue. Here is a mosque with a grave, and here is a mosque without a grave; leave the prayer in this mosque and pray in that one; because if you do that, you do not lose anything. But if it is said to the Muslim: leave the prayer in al-Masjid al-Nabawi, he has lost a thousand prayers with one prayer.
And therefore, you must know this reality. I recently returned from al-Madinah al-Munawwarah, having come back from there ten days ago. And I found there some Muslim youth who hold firmly to the Sunnah, meaning they are on the Salafi methodology; they say "Allah said, the Messenger of Allah said." It was difficult for him to pray in al-Masjid al-Nabawi, until he and others said to me that he does not pray in al-Masjid al-Nabawi while living in al-Madinah; because he wants to apply the general hadiths prohibiting building mosques over graves. So I drew his attention to the fact that this application is wrong; because your case, applying the general hadiths to al-Masjid al-Nabawi because it has a grave, is like the case of one who applies the general hadiths prohibiting prayer in the disliked times to the voluntary prayers with causes; it is said that this application here is wrong; why?
The scholars said: Because if we said: do not pray the greeting of the mosque in the time of dislike, do not pray the sunnah of wudu in the time of dislike, do not pray—for example—the eclipse prayer if it occurs in the time of dislike; then you have missed these prayers, and it is not possible for you to make them up. As for the voluntary prayers that are absolute and have no causes, you can pray them at any time. But when do you pray the sunnah of the greeting of the mosque? If you sit, the time passes. When do you pray the sunnah of wudu? If you do not pray after the wudu, the time passes. If you do not pray in the Messenger’s Mosque, you lose a thousand prayers; therefore, it is not correct to apply these hadiths that include every mosque on the face of the earth that has a grave; it is not correct to apply these hadiths to the Messenger’s Mosque (peace be upon him); because it is distinguished among the mosques by this virtue, just as the greeting of the mosque and the sunnah of wudu and similar voluntary prayers with causes are distinguished from other voluntary prayers. So those with causes are permissible in the times from which one is prohibited, just as praying in al-Masjid al-Nabawi is permissible; even though the original ruling is that it is prohibited; because the grave was found later in the Messenger’s Mosque (peace be upon him). But the virtue of a thousand prayers overcame this prohibition; the virtue of a thousand prayers overcame this prohibition, just as the virtue of not a thousand prayers nor less than that; rather, the virtue of the greeting of the mosque, and the virtue of the sunnah of wudu, overcame those with the—over the voluntary prayers that have no causes. This is what can be said in this short time.