كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَدْخُلُ الْخَلاَءَ، فَأَحْمِلُ أَنَا وَغُلاَمٌ إِدَاوَةً مِنْ مَاءٍ، وَعَنَزَةً، يَسْتَنْجِي بِالْمَاءِ.
Anas ibn Malik reported: When the Messenger of Allah ﷺ entered the toilet, I and a boy would carry a leather vessel of water and a short spear. He would clean himself with the water.
also in Sahih al-Bukhari 150, Sahih al-Bukhari 151, Sahih al-Bukhari 500