Muhammad bin Abdullah bin Salam narrates that his father (Sayyiduna Abdullah bin Salam, may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) came to us and said: "O people of Quba! Allah, the Mighty and Majestic, has praised you regarding purification; will you not tell me (what you do)?" We said: "O Messenger of Allah, we were commanded in the Torah to cleanse ourselves (istinja) with water."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13978