With whom did the Messenger of Allah, may Allah's prayers and peace be upon him, form a bond of brotherhood in the story of the brotherhood between the Muhajireen and the Ansar?

It is true that the Prophet, peace and blessings be upon him, established brotherhood between the Muhajirun (Emigrants) and the Ansar (Helpers) when he arrived in Medina. He formed brotherhoods among ninety men, half from the Muhajirun and half from the Ansar, based on mutual support and inheritance until the Battle of Badr. Then, the inheritance aspect was abrogated by the Almighty's saying: "But those of kinship are nearer to one another in the Scripture of Allah."

As for the Prophet, peace and blessings be upon him, establishing brotherhood with any other of his Companions, no authentic narration has been reported concerning it. The hadith narrated by Al-Tirmidhi and others about his establishing brotherhood between himself and Ali ibn Abi Talib, may Allah be pleased with him, is weak. Had he established brotherhood among the Muhajirun, Abu Bakr Al-Siddiq would have been the most deserving of his brotherhood.