Most people have a best friend who they favor amongst all of the people. The best friend of Prophet Muhammad (sallallaahu ‘alaihi wa sallam) was Abu Bakr As-Siddiq (may Allah be pleased with him).
He was the only person, other than the Prophet’s (sallallaahu ‘alaihi wa sallam) own wife, who accepted Islam immediately and believed in him from the first movement that he announced his Prophethood.
Abu Bakr (may Allah be pleased with him) always remained at the Prophet’s (sallallaahu ‘alaihi wa sallam) side and he had no reservations about spending his wealth for the sake of Islam and the Muslims. The Prophet’s Companions all recognized his superiority, yet he always remained humble and sincere towards all.
This is the story of Abu Bakr (may Allah be pleased with him) and his rise to leadership of the Muslim Ummah.