Abu Dawud Book 22, Hadith Number 3889.

Narated By AbuSalih Zakwan as-Samman : A man from Aslam tribe said: I was sitting with the Apostle of Allah (PBUH). A man from among his Companions came and said: Apostle of Allah! I have been stung last night, and I could not sleep till morning. He asked: What was that? He replied: A scorpion.

He said: Oh, had you said in the evening: “I take refuge in the perfect words of Allah from the evil of what He created,” nothing would have harmed you, Allah willing.