Jabir bin `Abdullah said, "Mu`adh bin Jabal used to pray with the Prophet (ﷺ) and then go to lead his
people in prayer Once he led the `Isha' prayer and recited Surat "Al-Baqara." Somebody left the
prayer and Mu`adh criticized him. The news reached the Prophet (ﷺ) and he said to Mu`adh, 'You are
putting the people to trial,' and repeated it thrice (or said something similar) and ordered him to recite
two medium Suras of Mufassal." (`Amr said that he had forgotten the names of those Suras).
Sahih al-Bukhari Book 10, Hadith 96