Asalamu alakium dear scholars my question is the following is it true that the prophet peace be upon him considered salman al Farsi to be one of the ahlul bayt during the battle of khandaq as many Islamic websites state in one narration however when looking at books of biographies and seerah l cannot find such a narration is there any books of hadeeth or books of the sunnah which state the following narration or similar to that in which the prophet peace be upon him names salman al Farsi to be one of his ahlul bayt your assistance in the matter will highly be appreciated jazakallahu khyran The following narration is given in many websites: O Messenger of Allah, in Persia when we feared an attack of cavalry, we would surround ourselves with a trench, so let us dig a trench about us now." The stunning suggestion was accepted. The course of the trench or Khandaq was carefully planned with Salman Al Farisi RA advising on the width and depth. Rasulullah made each section of the community responsible for a part of the trench. It was a massive undertaking. The work was strenuous and everyone, including Rasulullah dug and shifted the earth and boulders while chanting to keep the to keep their morale and spirits high. Salman Al Farisi RA being fit and strong and used to such hard labor is said to have done the work of ten men. While each section of the Muslims sought to claim Salman Al Farisi RA as its own, Rasulullah was moved to say, "Salman is one of us, the people of (my) household."
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu 'alayhi wa sallam, is His slave and Messenger.
As regards the Hadeeth that reads: “Salman is one of us –the people of the household of the Prophet”, it was attributed to the Prophet, sallallaahu 'alayhi wa sallam, but it was not confirmed from him.
Al-Albaani reported it with its different narrations in as-Silsilah adh-Dha’eefah, number 3704, and then said about it: "It is very weak." This narration was also classified as Dha’eef (weak) by ath-Thahabi in his commentary on Mustadrak al-Haakim.
However, Al-Albaani stated that this Hadeeth was authentically narrated by ‘Ali, may Allaah be pleased with him, as a Mawqoof Hadeeth (i.e. a Hadeeth with a chain of narrators terminating at the Companion level).
‘Ali, may Allaah be pleased with him, said about Salman, “He knows the first knowledge (i.e. of the previous revealed books) and the last one (i.e. the Quran and the Sunnah); he is a sea (of knowledge) that is very deep to the extent that you cannot reach its bottom; he is from us the family of the household [of the Prophet].” [Reported by Ibn Abu Shaybah, Ibn Sa’d and others] You can refer to as-Silsilah adh-Dha’eefah to find out more about the chain of narrators of this Hadeeth and its wording.
As regards whether or not it is Salman, may Allaah be pleased with him, who advised to dig the trench, then this is what is well-known in biography books, but we did not come across it in a Hadeeth with an authentic chain of narrators. The author of the book, “Ma Shaa’a wa lam yathbut fi as-seerah an-nabawiyyah (What is well-known but was not proven in the Prophet's biography) is: Salman's advice for digging the trench:
It was well-known in biography books that when the Prophet, sallallaahu 'alayhi wa sallam, heard that the Ahzab (the Combined Forces) wanted to attack al-Madeenah, he consulted with his companions, so Salman al-Faarisi advised him saying: “In Persia, when we were surrounded by the enemy, we used to surround ourselves with a trench.” Thereupon the Prophet, sallallaahu 'alayhi wa sallam, ordered the digging of the trench around al-Madeenah. Ibn Hajar said in Fat'h Al-Baari: “The one who pointed out to this was Salman according to the writers who write about war, among whom was Abu Ma’shar, who said: “Salman said: “[….]”; he quoted what Salman had said without mentioning any chain of narrators for it.
Abu Ma’shar is: Najeeh ibn Abdur-Rahmaan as-Sindi (who died in 171 A.H); Abu Daawood, at-Tirmithi, an-Nasaa’i and Ibn Maajah reported from him, but the majority of the scholars classified him as a weak narrator.
However, Imaam Ahmad is satisfied with him as he said: “He has a good insight about the battles (wars), but the deficiency is not in the weakness of Abu Ma’shar, but it is due to the fact that the narration is Mursal (a Hadeeth with a chain of narrators that does not include a companion of the Prophet, sallallaahu ‘alayhi wasallam) as he reported it without any chain of narrators.
Ibn Is'haaq did not mention the advice of Salman al-Faarisi, may Allaah be pleased with him, but he said:
“When the Prophet, sallallaahu 'alayhi wa sallam, heard about the Ahzab (the Combined Forces), that they were about to attack al-Madeenah, he dug a trench around al-Madeenah. So, the Prophet, sallallaahu 'alayhi wa sallam, took part in digging the trench with them in order to urge the Muslims to get the reward.”
But Ibn Hisham reported it without a chain of narrators as he said: “It was said that it was Salman al-Faarisi who pointed out to the Prophet, sallallaahu 'alayhi wa sallam, to dig the trench.” [End of quote]
Allah knows best.