Sunan an-Nasa'i 19
Sahih Graded by Abu Ghuddah Book of The Book of Purification · Hadith 19 of 5,758أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، قَالَ أَنْبَأَنَا إِسْمَاعِيلُ، عَنْ عَبْدِ الْعَزِيزِ بْنِ صُهَيْبٍ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا دَخَلَ الْخَلاَءَ قَالَ " اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنَ الْخُبُثِ وَالْخَبَائِثِ " .
Narrated by Anas bin Malik said
It was narrated that Anas bin Malik said:"The Messenger of Allah (ﷺ) entered Al-Khala' (the toilet) and said: 'Allahumma inni a'uthu bika min al-khubuthi wal-khaba'ith (O Allah, I seek refuge with You from male and female devils)."[1] [1] See Ma'alam As-Sunan by Al-Khattabi. And Al-Khala' is the area one relieves oneself in. It refers to outside or other than that, it should not be understood to mean toilet only
References
Sunan an-Nasa'i 19
In-book: Book 1, Hadith 19 Source: hadith-api (fawazahmed0)