The Makkan period of Islam was inscribed in the Muslim community's memory as a time of unbearable persecution and torture. Abuse was not meted out only to the poor and unprotected Musims (i.e., 'Ammar, Bilal, and Suhayb), but also to powerful Muslim members of the Qurayshi elite (i.e., Abu Bakr and 'Umar).  To protect his followers, the Messenger permitted those who were poor and unprotected to emigrate to Abyssinia. But he kept the powerful ones (i.e., 'Ali, Zubayr, Abu Bakr, 'Umar, and Sa'd ibn Abi Waqqas) in Makka, for Islam needed their support to spread and implant itself in Makka. These powerful Muslims went on to occupy the highest administrative positions of the Muslim state.
Abu Dharr was a poor, blunt, and upright bedouin who never restrained his faith or his feelings. When he heard Muhammad's declaration of Prophethood, he came to Makka and converted. The Messenger used to preach Islam secretly in the earliest stage of his Prophethood. Abu Dharr was very pious and austere. However, since public administration requires special skills, the Messenger did not accept his request for an administrative post, saying: "You cannot manage the people's affairs. Don't apply for such jobs, for we don't assign such jobs to those who apply for them." 
The Messenger refused Abu Dharr, but implied the caliphates of Abu Bakr, 'Umar, and 'Uthman. Holding the hands of Abu Bakr and 'Umar, he said: "I have four viziers, two in the heavens and two in the world. Those in the heavens are Gabriel and Michael; as for those in the world, they are Abu Bakr and 'Umar."  Concerning the caliphate of 'Uthman, he declared: "It will be a trial for him." 
 Muslim, "'Imara," 16–7.
 Muttaqi al-Hindi, Kanz al-'Ummal, 11:563, 13:15.
 Bukhari, "Fada'il al-Ashab," 5:7; Muslim, "Fada'il al-Sahaba," 29.