Whenever the Prophet ﷺ finished burying the deceased, he would stand at the grave and say, "Seek forgiveness for your brother, and ask that he be made firm, for he is now being questioned."
كان النبي ﷺ إذا فرغ من دفن الميت، وقف عليه فقال: استغفروا لأخيكم، وسلوا له التثبيت، فإنه الآن يسأل.
Abu Dawud (3221) narrated it from Ibrahim bin Musa Razi, who said, Hisham reported to us, from Abdullah bin Buhayr, from Hani, the freed slave of Uthman, from Uthman bin Affan, and he mentioned it. Its chain is hasan because of Hani, the freed slave of Uthman, who is Abu Saeed the Berber. Nasai said of him, "There is no harm in him," and Ibn Hibban mentioned him among the trustworthy narrators, so his hadith is hasan.Hakim (1/370) narrated it through this same route and said, "Sahih according to the standard of the chain." As for the prompting, Hafiz bin Qayyim said in his Zad (1/522–523), "It was not part of his ﷺ guidance to sit and recite at the grave, nor to prompt the deceased as people do today."As for the hadith narrated by Tabarani in his Kabir (8/298–299) from Abu Umama, it is not sound. It is what he narrated from Abu Aqeel Anas bin Muslim Khawlani, who said, Muhammad bin Ibrahim bin Ala Himsi reported to us, who said, Ismail bin Ayyash reported to us, who said, Abdullah bin Muhammad Qurashi reported to us, from Yahya bin Abu Kathir, from Saeed bin Abdullah Awdi, who said, I witnessed Abu Umama in his death throes, and he said, "When I die, do to me as the Messenger of Allah ﷺ commanded us to do with our dead. The Messenger of Allah ﷺ commanded us and said, 'When one of your brothers dies and you have leveled the earth over his grave, let one of you stand at the head of his grave and say, "O so-and-so, son of so-and-so," for he hears it though he does not answer. Then let him say, "O so-and-so, son of so-and-so," for he sits upright. Then let him say, "O so-and-so, son of so-and-so," for he says, "Guide us, may Allah have mercy on you," but you do not perceive it. So let him say, "Remember that which you departed this world upon, the testimony that there is no god but Allah, and that Muhammad is His servant and Messenger, and that you were content with Allah as Lord, with Islam as religion, with Muhammad as prophet, and with the Quran as guide." For Munkar and Nakir, one of them takes the hand of his companion and says, "Let us go, why should we sit with one whose argument has already been prompted to him," and Allah will be his advocate against the two of them.'"A man said, "O Messenger of Allah, what if he does not know his mother's name?" He said, "Then let him trace his lineage to Eve, saying, 'O so-and-so, son of Eve.'"Haythami said in Majma (3/45), "In its chain there is a group of narrators I do not recognize." Ibn Allan quoted in Futuhat Rabbaniya (4/196) from Ibn Hajar that he said, "This is a strange hadith, and the chain of the hadith through both routes is very daif." Hafiz bin Qayyim said, "This is a hadith whose attribution to the Prophet is not sound."