The Black Man

At this, Muqauqis said to the delegation, “How could you agree to make him your leader and superior, whereas he ought to have been your subordinate?” To this the delegation replied, “No, despite the fact that you see him as black, he is the best among us in knowledge, in nobility, in intellect and opinion, and we do not look down upon the black man.” Muqauqis said to ‘Ubada, “Come forward, O black [man] and speak to me gently, for I fear your colour, and if you were to talk to me in a harsh tone, my distress shall be all the greater.” ‘Ubada, noticing Muqauqis’ fear of black people, said, “We have in our army a thousand people darker than me.”

Ibn Khaldun on the Caliphate

Appointing a leader (imam) is obligatory. Its mandatory nature is known through revelatory law (shar‘) by the consensus of the Companions and the next generation of Followers, because the Companions of the Prophet (ﷺ) hastened upon his death to pledge allegiance and submit consideration of their affairs to Abu Bakr (May God be pleased with him). And it was thus in every age thereafter, and the matter was established as consensus indicating the obligation of appointing a leader (imam).