I heard the Messenger of Allah ﷺ say, "No one delivers public admonitions except a ruler, one appointed by a ruler, or one showing off."
سمعت رسول الله ﷺ يقول: لا يقص إلا أمير، أو مأمور، أو مختال.
Abu Dawud (3665) narrated it from Mahmud bin Khalid, from Abu Mishar, from Abbad bin Abbad Khawwas, from Yahya bin Abu Amr Saybani, from Amr bin Abdullah Saybani, from Awf bin Malik, and he related it.Its isnad is hasan, because of Abbad bin Abbad, who is truthful (saduq). Amr bin Abdullah Saybani is acceptable (maqbul), because he has a corroborator, Kathir bin Mura corroborated him, and he is trustworthy (thiqah).Imam Ahmad (24005) narrated it from Abu Asim, who said, Abdul-Hameed informed us, who said, Salih bin Urayb told us, from Kathir bin Mura, from Awf bin Malik, who said, Awf bin Malik entered the masjid of Hims. He said, and the people were gathered around a man, so he said, "What is this gathering?" They said, "Kaab is giving a sermon (qass)." He said, "Woe to him, has he not heard the saying of the Messenger of Allah ﷺ, 'No one should give a sermon except a commander, one who has been appointed, or a self-conceited person'?"Bazzar (2662) and Tabarani (18/55) also narrated it through this same route. Ahmad (23974) narrated it through another route from Awf bin Malik with the wording, "Sermon-givers are three, a commander, one who has been appointed, or a self-conceited person."