Ablutions (Wudu')
4/10. Chapter:
Providing water at lavatories (for washing the private parts after answering the call of nature)
Sahih Bukhari
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ، قَالَ حَدَّثَنَا هَاشِمُ بْنُ الْقَاسِمِ، قَالَ حَدَّثَنَا وَرْقَاءُ، عَنْ عُبَيْدِ اللَّهِ بْنِ أَبِي يَزِيدَ، عَنِ ابْنِ عَبَّاسٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم دَخَلَ الْخَلاَءَ، فَوَضَعْتُ لَهُ وَضُوءًا قَالَ " مَنْ وَضَعَ هَذَا ". فَأُخْبِرَ فَقَالَ " اللَّهُمَّ فَقِّهْهُ فِي الدِّينِ ".
Narrated Ibn `Abbas: Once the Prophet (ﷺ) entered a lavatory and I placed water for his ablution. He asked, "Who placed it?" He was informed accordingly and so he said, "O Allah! Make him (Ibn `Abbas) a learned scholar in religion (Islam).
Reference : Sahih al-Bukhari 143In-book reference : Book 4, Hadith 9USC-MSA web (English) reference : Vol. 1, Book 4, Hadith 145