1.3.2 Details concerning this historic “Mu’akhaah” (pact of brotherhood) and the personalities involved in it
The following came related in “At-Tabaqat Al-Kubra”, of Ibn Sa’d (2/12): Abdullah bin Muhammad bin ‘Umar bin ‘Ali related from his father:

“When the Messenger of Allah (peace be upon him) came to Al- Madinah, he established a pact of brotherhood between the Muhajirin, some of them with others from among them, and he also established a brotherhood (of pairs) between the Muhajirin and the Ansar. The establishment of brotherhood did not take place except prior to Badr. He (peace be upon him) established brotherhood between them upon the basis of the truth and providing assistance/support. Then he made a brotherhood pairing between himself and ‘Ali Ibn Abi Talib”. Also, in “At-Tabaqat Al-Kubra”, of Ibn Sa’d (2/12): Abdullah bin Muhammad bin ‘Umar bin ‘Ali related from his father:

“That when the Prophet (peace be upon him) established a pact of brotherhood between his companions, he placed his hand upon the shoulder of ‘Ali and then said: “You are my brother, you inherit from me and I inherit from you”. Then when the Aayah related to inheritance was revealed that was cut off (i.e. the right of inheritance based on this brotherhood pairing).
Ibn Sa’d, in his “Tabaqat Al-Kubra” (2/12) also related from ‘Asim bin ‘Umar bin Qatadah who said:

“The Messenger of Allah (peace be upon him) established a brotherhood (of pairs) between ‘Ali bin Abi Talib and Sahl bin Hanif”.
In “Ikhtisaar Al-Maghazi Wa s-Siyar” of Ibn Abdul Barr (p.20 Shamela Electronic Book Program) stated under the heading: “The formation of brotherhood by the Messenger of Allah (peace be upon him) between the Muhajirin and the Ansar”:
“The Messenger of Allah (peace be upon him) established the brotherhood between the Muhajirin and the Ansar, after building the Masjid. It has been said that the brotherhood was established whilst the Masjid was being built, between the Muhajirin and the Ansar, upon the basis of providing assistance/support and upon the truth. According to that, they would inherit from each other and not based upon blood relation, until the following was revealed: “But those of [blood] relationship are more entitled [to inheritance] in the decree of Allah” (8:75). Abu Dawud At-Tayalisi related from Ibn ‘Abbas: “The Messenger of Allah (peace be upon him) made a brotherhood between his companions; the Muhajirin and the Ansar, and they inherited from each other, until: “But those of [blood] relationship are more entitled [to inheritance] in the decree of Allah” (8:75) was revealed.
Sa’eed bin Dawud stated: “We have conveyed and recorded from our Shuyukh (i.e. teachers) that he (peace be upon him): Established a brotherhood, on that day, between Abu Bakr As-Siddiq and Kharija bin Zaid bin Abu Zuhair, and between ‘Umar ibn ul-Khattab and ‘Uwaim bin Sa’idah”. He said: And it has been said that it was made between ‘Umar ibn ul-Khattab and Mu’adh bin ‘Afraa’. He said: And it has (also) been said: The brotherhood was established between ‘Umar and ‘Atban bin Malik, ‘Uthman bin ‘Affan and ‘Aws bin Thabit, ‘Ali ibn Abi Talib and Sahl bin Hanif, Zaid bin Haritha and Usaid bin Al- Hudair, Abu Marthad Al-Ghanwiy and ‘Ubadah bin Samit, Az-Zubair and Ka’b bin Malik, Talha and Ubayy bin Ka’b, Sa’d bin Abi Waqqas and Sa’d bin Mu’adh, Abdur Rahman bin ‘Auf and Sa’d bin Ar-Rabee’, Abdullah bin Jahsh and ‘Asim bin Thabit, Abu Hudhaifa bin ‘Utbah and ‘Abbad bin Bishr. ‘Utbah bin Ghazwan and Abu Dujana, Mus’ab bin ‘Umair and Abu Ayub, Ibn Mas’ud and Mu’adh bin Jabal, Abu Salamah bin Abdul Asad and Sa’d bin Khuthaimah, ‘Ammar and Hudhaifa bin Al-Yaman, Abu ‘Ubaidah and Muhammad bin Maslama, Uthman bin Mazh’un and Abu Al-Haitham bin At-Taihan, and between Salman Al-Farisi and Abu Ad-Dardaa’. Al-Hafizh Abu ‘Umar, may Allah be pleased with him, said: Sanid mentioned this and did not attribute through a line of transmission to anyone, merely saying that it was conveyed to him. What is authentic, according to the scholars of the biographies and reports, in respect to the establishment of brotherhood, which was undertaken by the Messenger of Allah (peace be upon him) between the Muhajirin and the Ansar, when he arrived in Al-Madinah, is that: He established brotherhood between Abu Bakr As-Siddiq and Kharija bin Zaid bin Abu Zuhair, ‘Umar ibn ul-Khattab and ‘Atban bin Malik, Uthman bin ‘Affan and Aws bin Thabit bin Al-Mundhir (the brother of Hassan bin Thabit) and that he established brotherhood between ‘Ali bin Abi Talib and himself (peace be upon him). He said to him: “You are my brother in the Dunya (life of this world) and the hereafter”. (Following the mention of the line of transmission) Ibn ‘Abbas related: “That the Prophet (peace be upon him) said to ‘Ali: “You are my brother and my companion”. (Following the mention of the line of transmission) Ibn ‘Abbas related: Ali use to say: “By Allah, I am the brother of the Messenger of Allah (peace be upon him) and his Wali”. (Following the mention of the line of transmission) ‘Abbad bin Abdullah said: I heard ‘Ali saying: “I am Abdullah (the slave of Allah) and the brother of His Messenger and none will say that after me except a great liar and fabricator”. (Following the mention of the line of transmission) Abu Suleiman Al-Jahaniy, meaning Zaid bin Wahb, said: I heard ‘Ali saying from the Minbar (pulpit): “I am Abdullah (the slave of Allah) and the brother of His Messenger. No one has said that before me and none will say it after me except for a great liar and fabricator”.

“The Messenger of Allah (peace be upon him) made a pact of brotherhood in Makkah between Abu Bakr As-Siddiq and ‘Umar bin Al-Khattab. Then when the Messenger of Allah (peace be upon him) arrived in Al-Madinah, he invalidated that brotherhood (i.e. amongst the companions) apart for the brotherhood pact between him and ‘Ali bin Abi Talib and the pact which was between Hamza bin Abdul Muttalib and Zaid bin Haritha”. He said: It was related from Jabir bin Abdullah bin ‘Amr bin Haram Al-Ansari: “That when the Messenger of Allah (peace be upon him) made the brotherhood pact between the Muhajirin and the Ansar, he made a brotherhood between Abu Bakr As-Siddiq and Kharija bin Zaid bin Abi Zuhair Al-Khazraji” [End of Quote].
In “Al-Mufahhim lima Ashkala min Talkhees Kitaab Muslim” (21/38) it was stated:

Abu ‘Umar said: “The correct view as held by the scholars of Seera and reports in respect to the “Mu’akhaah” (brotherhood) which the Messenger of Allah (peace be upon him) concluded between the Muhajirin (emigrants) and the Ansar (helpers), when he came to Al- Madinah, was that it took place after his building of the Masjid and it was upon the basis of the provision of assistance/support and the Haqq (truth) …” He then proceeded with it details as have previously been mentioned and then said: “I said: And it came stated in book of Muslim as related by Anas: “That he concluded a brotherhood between Abu ‘Ubaida bin Al-Jarrah and between Abu Talha”. Abu ‘Umar said: He concluded a brotherhood between Abu ‘Ubaida and Sa’d bin Mu’adh. And the first is not in the book of Muslim …” [End of Quote].
I say: That is not necessarily the case. The speech of Abu ‘Umar could be based upon a number of reports which support one another whilst there is no rational or Shar’iy (legal) prevention (Mani’) for the Prophet (peace be upon him) to have concluded a brotherhood between Abu ‘Ubaidah and Sa’d bin Mu’adh and Abi Talha at the same time. A person can have a number of brothers byu blood at the same time and this could be the same. Or he (peace be upon him) could have concluded a brotherhood between Abu ‘Ubaida and Sa’d bin Mu’adh first and then concluded a brotherhood between him and Abu Talha when he became Muslim at a later time. In any case, the number of the Ansar was much greater than the Muhajirin at that time and they were competing among themselves to provide accommodation to the Muhajirin and take care of them. Consequently, would it be strange for a Muhajir to have multiple brothers from the Ansar?!