Sahih Adab al-Mufrad

675/875 From Ibn Umar who said: Two men from the east came as preachers during the time of the Messenger of Allah, peace be upon him. They stood up and spoke, then sat down. Then Thabit ibn Qays, the preacher of the Messenger of Allah, peace be upon him, stood up and spoke, and the people were amazed at their speech. The Messenger of Allah, peace be upon him, then stood up to preach and said: "O people! Say what you have to say, for indeed splitting hairs in speech is from the Shaytan." Then the Messenger of Allah, peace be upon him, said: "Indeed, some eloquence is magic."

676/876 From Anas who said: A man delivered a sermon before Umar and spoke at length, so Umar said: "Indeed, excessive speech in sermons is among the rants of Satan."(3).

677/877- From Abu Yazid – or: Ma'n ibn Yazid – that the Prophet, peace be upon him, said: "Gather in your mosques, and whenever a group gathers, let them inform me." The first to come to us arrived, sat down, and one of us spoke, then said: "Praise be to Allah, for whom there is no destination for praise except Him, nor any outlet beyond Him." He became angry and stood up, so we blamed each other among ourselves and said: "The first to come to us has left; he went to another mosque and sat there." So we went to him, spoke to him, and he came with us and sat in his seat or near his seat. Then he said: "Praise be to Allah, who places whatever He wills before Him, and whatever He wills behind Him. Indeed, among eloquence there is magic." Then he commanded us and taught us.