مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 370
Purification
How to act when relieving oneself - Section 3
وَعَن سلمَان قَالَ قَالَ لَهُ بعض الْمُشْركين وَهُوَ يستهزئ بِهِ إِنِّي لأرى صَاحبكُم يعلمكم كل شَيْء حَتَّى الخراءة قَالَ أَجَلْ أَمَرَنَا أَنْ لَا نَسْتَقْبِلَ الْقِبْلَةَ وَلَا نَسْتَنْجِيَ بِأَيْمَانِنَا وَلَا نَكْتَفِيَ بِدُونِ ثَلَاثَةِ أَحْجَارٍ لَيْسَ فِيهَا رَجِيعٌ وَلَا عَظْمٌ. رَوَاهُ مُسْلِمٌ وَأحمد وَاللَّفْظ لَهُ
Salman said that a polytheist jestingly remarked, “I see that your friend teaches you even about your excrement,” to which he replied, “Yes, he has commanded us not to face the qibla, or cleanse ourselves with our right hands, or be satisfied with less than three stones among which there is no dung or bone.” Muslim and Ahmad transmitted it, the wording being Ahmad’s.
Mishkat al-Masabih, 370صَحِيح (الألباني)