Musnad Ishaq

Benefits:
It is stated in Sahih Bukhari: ((There is nothing of the human being that does not decay except for one bone, and that is the coccyx (the last bone of the spine), and from it the creation will be reassembled on the Day of Resurrection.)) (Bukhari, no. 4935)... "Everything of the human being decays except for one bone, which is the last vertebra of the spine; on the Day of Resurrection, creation will begin from it."

It is understood from this that in the grave, the human body gradually turns into dust, to the extent that even the bones become dust. However, those whose bodies Allah, the Possessor of Majesty, wishes to preserve, nothing happens to their bodies.

It is narrated in Sahih Bukhari that during the reign of Abdul Malik bin Marwan, when the wall of the blessed chamber of the Noble Prophet sallallahu alayhi wa sallam collapsed and people began to raise it (higher), a foot appeared there. People became alarmed, thinking that it was the blessed foot of the Noble Prophet sallallahu alayhi wa sallam. There was no one who could recognize the foot. Eventually, Urwah bin Zubair said, "No, by Allah, this is not the foot of the Messenger of Allah sallallahu alayhi wa sallam, rather it is the foot of Umar radi Allahu anhu." (Bukhari, no. 1390)

It is narrated in Muwatta Imam Malik from Abdur Rahman bin Abu Sa'sa'ah rahimahullah that Sayyiduna Amr bin Jamuh and Sayyiduna Abdullah bin Amr Ansari Aslami were both martyred in the Battle of Uhud. The flow of water had unearthed their grave, and it was close to being washed away. Both were buried in the same grave. Thus, their grave was dug up so that their bodies could be moved and buried elsewhere. There was no change in the bodies of either of them; it seemed as if they had just been martyred yesterday. When one of them was wounded, he had placed his hand on the wound due to the pain, and when they tried to move his hand (while reburying), it returned to the same place (on the wound). The incident of the grave being dug up occurred forty-six years after the Battle of Uhud. (Muwatta Malik, Book of Jihad, Chapter: Burial of Two in One Grave out of Necessity, no. 1704)

However, the bodies of the Prophets alayhimus salam remain preserved in their graves until the Day of Resurrection. As the Messenger of Allah sallallahu alayhi wa sallam said: "Allah, the Exalted, has made the bodies of the Prophets alayhimus salam forbidden for the earth (to consume)." (Sahih Abi Dawud, no. 925)

Allamah Ibn Abd al-Barr rahimahullah has stated that in this ruling, besides the Prophets alayhimus salam, martyrs are also included. Allamah Qurtubi rahimahullah has even included the muezzin who calls the adhan with righteous intention. Furthermore, Qadi Iyad rahimahullah, in his commentary on this hadith, says: The purpose of the hadith is that the earth consumes the bodies of all the children of Adam, except for specific bodies such as those of the Prophets alayhimus salam, etc. (Fath al-Bari: 8/553, Hadith no. 4814)

Allamah Ibn al-Jawzi rahimahullah, quoting Ibn Aqil, writes (regarding the aforementioned hadith that the coccyx remains): There is a secret of Allah in this, which no one knows except Him. For the One who can bring into existence from non-existence, it is not necessary for Him to require the leaven of anything. (Fath al-Bari: 8/553-554)