Sunan Ibn Mājah 3518

The full narration

It was narrated that Abu Hurairah said:“A scorpion stung a man and he did not sleep all the night. It was said to the Prophet (ﷺ): ‘So- and-so was stung by a scorpion and he did not sleep all the night.’ He said: ‘If he had said, last night: A’udhu bikalimatil-lahit-tammati min sharri ma khalaq (I seek refuge in the Perfect Words of Allah from the evil of that which He has created), the scorpion sting would not have harmed him, until morning.’”