Sunan an-Nasa'i 40
It was narrated from Abu Hurairah that the Prophet (ﷺ) said:
"I am like a father teaching you. When any one of you goes to Al-Khala' (the toilet), let him not face toward the Qiblah nor turn his back toward it, and let him not clean himself with his right hand." And he used to tell them to use three stones, and he forbade using dung or old bones.
أَخْبَرَنَا يَعْقُوبُ بْنُ إِبْرَاهِيمَ، قَالَ حَدَّثَنَا يَحْيَى، - يَعْنِي ابْنَ سَعِيدٍ - عَنْ مُحَمَّدِ بْنِ عَجْلاَنَ، قَالَ أَخْبَرَنِي الْقَعْقَاعُ، عَنْ أَبِي صَالِحٍ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏
"‏ إِنَّمَا أَنَا لَكُمْ مِثْلُ الْوَالِدِ أُعَلِّمُكُمْ إِذَا ذَهَبَ أَحَدُكُمْ إِلَى الْخَلاَءِ فَلاَ يَسْتَقْبِلِ الْقِبْلَةَ وَلاَ يَسْتَدْبِرْهَا وَلاَ يَسْتَنْجِ بِيَمِينِهِ ‏"‏ وَكَانَ يَأْمُرُ بِثَلاَثَةِ أَحْجَارٍ وَنَهَى عَنِ الرَّوْثِ وَالرِّمَّةِ ‏.‏