Sahih Muslim Book 004, Hadith Number 1888.
Chapter : Warning on neglecting Jumu'a.
Ibn 'Abbas reported: Dimad came to Mecca and he belonged to the tribe of Azd Shanu'a, and he used to protect the person who was under the influence of charm. He heard the foolish people of Mecca say that Muhammad (may peace be upon him) was under the spell. Upon this he said: If I were to come across this man, Allah might cure him at my hand. He met him and said: Muhammad, I can protect (one) who is under the influence of charm, and Allah cures one whom He so desires at my hand. Do you desire (this)? Upon this the Messenger of Allah (may peace be upon him) said: Praise is due to Allah, we praise Him, ask His help; and he whom Allah guides aright there is none to lead him astray, and he who is led astray there is none to guide him, and I bear testimony to the fact that there is no god but Allah, He is One, having no partner with Him, and that Muhammad is His Servant and Messenger. Now after this he (Dimad) said: Repeat these words of yours before me, and the messenger of Allah (may peace be upon him) repeated these to him thrice; and he said I have heard the words of soothsayers and the words of magicians, and the words of poets, but I have never heard such words as yours, and they reach the depth (of the ocean of eloquence); bring forth your hand so that I should take oath of fealty to you on Islam. So he took an oath of allegiance to him. The Messenger of Allah (may peace be upon him) said: It (this allegiance of yours) is on behalf of your people too. He said: It is on behalf of my people too. The Messenger of Allah (may peace be upon him) sent an expedition and the flying column passed by his people. The leader of the flying column said to the detachment: Did you find anything from these people? One of the people said: I found a utensil for water. Upon this he (the commander) said: Return it, for he is one of the people of Dimad.