Sahih al-Bukhari Book 10, Hadith 88
The Prophet (ﷺ) said, "Listen and obey (your chief) even if an Ethiopian whose head is like a raisin were
made your chief."
When the earliest emigrants came to Al-`Usba a place in Quba', before the arrival of the Prophet- Salim, the slave of Abu Hudhaifa, who knew the Qur'an more than the others used to lead them in prayer.
Allah's Messenger (ﷺ) said, "If the Imam leads the prayer correctly then he and you will receive the rewards but if he makes a mistake (in the prayer) then you will receive the reward for the prayer and the sin will be his."