Sahih al-Bukhari 150
Sahih al-Bukhari · Book 4: Ablutions (Wudu') · To wash the private parts with water after answering the call of nature
Narrated Anas bin Malik:
حَدَّثَنَا أَبُو الْوَلِيدِ، هِشَامُ بْنُ عَبْدِ الْمَلِكِ قَالَ حَدَّثَنَا شُعْبَةُ ، عَنْ أَبِي مُعَاذٍ ـ وَاسْمُهُ عَطَاءُ بْنُ أَبِي مَيْمُونَةَ ـ قَالَ سَمِعْتُ أَنَسَ بْنَ مَالِكٍ ، يَقُولُ كَانَ النَّبِيُّ صلى الله عليه وسلم إِذَا خَرَجَ لِحَاجَتِهِ أَجِيءُ أَنَا وَغُلاَمٌ مَعَنَا إِدَاوَةٌ مِنْ مَاءٍ. يَعْنِي يَسْتَنْجِي بِهِ.
Whenever Allah's Messenger (ﷺ) went to answer the call of nature, I along with another boy used to accompany him with a tumbler full of water. (Hisham commented, "So that he might wash his private parts with it.)"