Sunan Ibn Majah, Book 31, Hadith 3647 (In-Book) ⓘ
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: ‘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.’”
حَدَّثَنَا إِسْمَاعِيلُ بْنُ بَهْرَامَ، حَدَّثَنَا عُبَيْدُ اللَّهِ الأَشْجَعِيُّ، عَنْ سُفْيَانَ، عَنْ سُهَيْلِ بْنِ أَبِي صَالِحٍ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ لَدَغَتْ عَقْرَبٌ رَجُلاً فَلَمْ يَنَمْ لَيْلَتَهُ فَقِيلَ لِلنَّبِيِّ ـ صلى الله عليه وسلم ـ إِنَّ فُلاَنًا لَدَغَتْهُ عَقْرَبٌ فَلَمْ يَنَمْ لَيْلَتَهُ . فَقَالَ " أَمَا إِنَّهُ لَوْ قَالَ حِينَ أَمْسَى أَعُوذُ بِكَلِمَاتِ اللَّهِ التَّامَّاتِ مِنْ شَرِّ مَا خَلَقَ - مَا ضَرَّهُ لَدْغُ عَقْرَبٍ حَتَّى يُصْبِحَ " .
also referenced under: Hadith 3518 (Reference) & Volume 4, Book 31, Hadith 3518 (DarusSalam)