What is the evidence, from the Sunnah, which proves the validity of using curing verses for ailments and magic?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

According to the texts of the Quran and the Sunnah of the Prophet, sallallaahu ‘alayhi wa sallam, the Book of Allaah, the Exalted, is a remedy for both physiological and psychological  diseases that may afflict humans. The Quran is also a remedy for symptoms resulting from magic spells. Referring to this, Allaah the Exalted Says (what means):

•        {O mankind, there has to come to you instruction from your Lord and healing for what is in the breasts and guidance and mercy for the believers} [Quran 10: 57] 

•        {And We send down of the Quran that which is healing and mercy for the believers} [Quran 17: 82]

As for the Sunnah (Prophetic tradition), it was reported on the authority of Abu Sa‘eed Al-Khudri that he recited the Chapter Al-Faatihah over a person who had been stung by a poisonous scorpion or snake, then Allaah The Exalted cured him. When he told the Prophet, sallallaahu ‘alayhi wa sallam, about this he approved of his action. [Al-Bukhari]  

Likewise, it was also reported on the authority of ‘Aa’ishah that the Prophet, sallallaahu ‘alayhi wa sallam, came in while a woman was performing Ruqyah for her. The Prophet, sallallaahu ‘alayhi wa sallam, ordered the woman to perform Ruqyah using verses of the Quran.  [Ibn Hibbaan]

Allaah Knows best.