Sahih al-Bukhari, Hadith 143 ⓘ
Narrated Ibn `Abbas: Once the Prophet 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).
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 ".
also referenced under: Book 4, Hadith 9 (In-Book) & Volume 1, Book 4, Hadith 145 (USC-MSA)