Is it sahih that munkar & nakir will come into grave by biting through earth by their teeth? And when they awaken the person in grave, that person will say: leave me I have to pray my asr?
Praise be to Allaah.
It is narrated in saheeh reports that the two angels whose task it is to question the deceased are black and blue, and one is called al-Munkar and the other is called al-Nakeer.
Al-Tirmidhi (1071) narrated that Abu Hurayrah (may Allaah be pleased with him) said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “When the deceased – or one of you – is buried, there come to him two black and blue angels, one of whom is called al-Munkar and the other al-Nakeer. They say: ‘What did you say about this man?’ and he says what he used to say: ‘He is the slave of Allaah and His Messenger. I bear witness that there is no god but Allaah and that Muhammad is His slave and Messenger.’ They say: ‘We knew that you would say that.’ Then his grave is made spacious for him, seventy cubits by seventy, and it is illuminated for him. Then it is said to him: ‘Sleep,’ and he says: ‘May I go back to my family and tell them?’ They say: ‘Sleep like the bridegroom who will be woken by none but the dearest of his family to him,’ until Allaah raises him from that resting-place of his.”
But if he is a hypocrite he says: ‘I heard the people saying something so I said something like what they said. I do not know.’ They say: ‘We knew that you would say that.’ Then it is said to the earth: ‘Squeeze him.’ So it squeezes him until his ribs interlock, and he will continue to be tormented therein until Allaah raises him from that resting-place of his.”
This hadeeth was classed as hasan by al-Albaani in Saheeh al-Tirmidhi.
With regard to the hadeeth of ‘Umar to which you refer, it was narrated via da’eef (weak) isnaads, such as the mursal report narrated by ‘Abd al-Razzaaq in his Musannaaf (6738) from ‘Amr ibn Dinar, according to which the Prophet (peace and blessings of Allaah be upon him) said to ‘Umar: “How will you deal, O ‘Umar, with the two testers in the grave, when they come to you digging the earth with their eyeteeth, stepping on their hair (because it is so long), their eyes like dazzling lightning and their voices like deafening thunder, with a whip so heavy that if the whole world were to gather together to lift it, they would not be able?” ‘Umar said: I will be as I am today. He said: As you are today? He said: Then I shall take care of them for you, in sha Allaah.”
Al-‘Iraaqi said in Takhreej al-Ihya’ (4/223): This was narrated like this, as a mursal report, by Ibn Abi’l-Dunya in Kitaab al-Quboor, and its men are thiqaat (trustworthy). Al-Bayhaqi said in al-I’tiqaad: We have narrated it via a saheeh isnaad in a mursal report from ‘Ata’ ibn Yasaar.
I say: Ibn Battah narrated it in a mawsool report in al-Ibaanah, from the hadeeth of Ibn ‘Abbaas, and it was narrated by al-Bayhaqi in al-I’tiqaad from the hadeeth of ‘Umar, but he said it is ghareeb with this isnaad, which was narrated only by Mufaddal. Ahmad and Ibn Hibbaan also narrated from the hadeeth of ‘Abd-Allaah ibn ‘Umar that ‘Umar said: “Will our awareness be restored to us?” He said: “Yes, just as you are today.” ‘Umar said: “Then I will throw a stone in his mouth.” end quote.
Professor Fareej ibn Saalih al-Bahlaal said in his commentary on al-I’tiqaad by al-Bayhaqi (p. 254), after referring to the da’eef isnaad: Perhaps by virtue of these isnaads and corroborating reports its isnaad may be hasan. End quote.
The questions which the angels put to the deceased in his grave are: Who is your Lord? What is your religion? Who is this man who was sent among you?
And Allaah knows best.