رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 1648
The Book of the Prohibited actions
Prohibition of using the right hand for cleaning after toilet without a valid reason
عَنْ أَبِي قَتَادَةَ رَضِيَ اللَّه عَنْهُ عَنِ النَّبِيِّ صَلَّى اللَّه عَلَيْهِ وَسَلَّمَ قَالَ: إِذَا بَالَ أَحَدُكُمْ، فَلاَ يؤخذن ذَكَرَهُ بِيَمِينِهِ، وَلاَ يَسْتَنْجِي بِيَمِينِهِ، وَلاَ يَتَنَفَّسْ فِي الإِنَاءِ ((مُتَّفَقٌ عَلَيْهِ)) وفي الباب أحاديث كثيرة صحيحة.
Abu Qatadah (May Allah be pleased with him) said: The Prophet (ﷺ) said, "Do not touch your private parts with your right hand while urinating, nor for washing or cleaning (your private parts); and do not breathe into the drinking vessel from which you drink." [Al-Bukhari and Muslim].
Riyad as-Salihin, 1648