Musannaf Ibn Abi Shayba 1:1630

Yahya ibn Adam narrated to us, he said: Malik ibn Mighwal narrated to us, he said: I heard Sayyar Abu al-Hakam—more than once—narrating from Shahr ibn Hawshab, from Muhammad ibn Yusuf ibn Abdullah ibn Salam, who said: When the Messenger of Allah (peace be upon him) came to us—meaning Quba—he said: "Allah has praised you well regarding purification. Will you not inform me?" He said: Meaning the saying of the Exalted, "In it are men who love to purify themselves, and Allah loves those who purify themselves." He said: So they said, "O Messenger of Allah, we find it written upon us in the Torah: cleansing (istinja) with water."