Sunan Abi Dawud 3420

Kharijah b. al-Salt quoted his paternal uncle as saying that he passed by a clan (of the Arab) who came to him and said:You have brought what is good from this man. Then they brought a lunatic in chains. He recited Surat al-Fatihah over him three days, morning and evening. When he finished, he collected his saliva and then spat it out, (he felt relief) as if he were set free from a bond. They gave him something (as wages). He then came to the Prophet (ﷺ) and mentioned it to him. The Messenger of Allah (ﷺ) said: Accept it, for by my life, some accept it for a worthless charm, but you have done so far a genuine one