Musnad Ahmad 27:1237

Abu Amir Abd al-Malik ibn Amr narrated to us, Zuhayr narrated to us, from Zayd ibn Aslam, who said: I heard Ibn Umar say: Two men came from the East as orators during the time of the Messenger of Allah, may Allah bless him and grant him peace. They stood and spoke, then sat down. Then Thabit ibn Qays, the orator of the Messenger of Allah, may Allah bless him and grant him peace, stood and spoke, then sat down. The people were amazed by their speech. The Prophet, may Allah bless him and grant him peace, stood and said: "O people, say what you have to say, for the splitting of speech is only from Satan." The Prophet, may Allah bless him and grant him peace, said: "Indeed, some eloquence is magic."