Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates that when the Messenger of Allah (peace and blessings of Allah be upon him) would go out to relieve himself, I and another (Ansari) boy would follow behind him carrying a water vessel. When he finished relieving himself, I would hand him the vessel and the Messenger of Allah (peace and blessings of Allah be upon him) would perform istinja (cleaning).