Is it authentic that the Muslims pray in their graves?

The questioner : My teacher, the hadith regarding the prayer of the believers in their graves is authentic in the rulings on funerals.

The Shaykh : Yes, exactly.

The questioner : Does this mean that there is a religious obligation to perform deeds in the graves?

The Shaykh : Is there a religious obligation in Paradise?

The questioner : There is nothing.

The Shaykh : There is no obligation; there is glorification of Allah in Paradise.

The questioner : There is.

The Shaykh : There is praise and glorification in Paradise; it is like it is.
The student : What is your opinion regarding the opinion of al-Nawawi?

The Shaykh : And he is...

The questioner : That is to say... that the eternal obligation and between...
The student : This may not be an obligation at all, meaning its purpose is...

The Shaykh : No, this is not an obligation; this means giving thanks to Allah, Mighty and Majestic.
The student : Just as one is accustomed to in this world, it continues...
The student : But we do not know the manner of this prayer...

The Shaykh : All matters of the unseen are not known; what are you going to do to make it official...

The questioner : Is there a difference between it and the prayer of the prophets?

The Shaykh : In what?

The questioner : Is there a difference between it and the prayer of the prophets, or we do not know?

The Shaykh : We do not know. Did you know the prayer of the prophets? Of course not; that is even more so.