Imām Bukhārī said: And Muhammad ibn Bashshār narrated to us, he said: Ghundar narrated to us, he said: Shu'bah narrated to us, from 'Amr, he said: I heard Jābir ibn 'Abdullāh, may Allāh be pleased with them both, he narrated that:

Mu'ādh ibn Jabal, may Allāh be pleased with him, used to pray with the Prophet ﷺ, then he would go and lead his people in prayer. So he led the 'Ishā' prayer, and in it he recited Sūrat al-Baqarah. So a person left the prayer, so it is as if Mu'ādh spoke ill of him. Then this matter reached the Prophet ﷺ, so he said three times: You are indeed a fitnah-causer, you are indeed a fitnah-causer, you are indeed a fitnah-causer — or he said: You are a fitnah-causer, you are a fitnah-causer, you are a fitnah-causer — and he commanded him to recite two of the medium-length sūrahs of al-Mufassal. 'Amr said: I do not remember them.