Sahih al-Bukhari 144
صحيح البخاري#144Sahihحَدَّثَنَا آدَمُ، قَالَ حَدَّثَنَا ابْنُ أَبِي ذِئْبٍ، قَالَ حَدَّثَنَا الزُّهْرِيُّ، عَنْ عَطَاءِ بْنِ يَزِيدَ اللَّيْثِيِّ، عَنْ أَبِي أَيُّوبَ الأَنْصَارِيِّ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا أَتَى أَحَدُكُمُ الْغَائِطَ فَلاَ يَسْتَقْبِلِ الْقِبْلَةَ وَلاَ يُوَلِّهَا ظَهْرَهُ، شَرِّقُوا أَوْ غَرِّبُوا ".
Narrated Abu Aiyub Al-Ansari:Allah's Messenger (ﷺ) said, "If anyone of you goes to an open space for answering the call of nature he should neither face nor turn his back towards the Qibla; he should either face the east or the west
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 4:10