Musnad Ahmad 5:236

'Abdullah narrated to us, Muhammad bin Ja'far al-Warkani narrated to us, Sharik narrated to us, from Makhariq, from Tariq, who said: 'Ali addressed us and said: "We do not have anything of the revelation—or he said: a book from the Messenger of Allah, may Allah bless him and grant him peace—except what is in the Book of Allah, and this scroll which is attached to my sword"—and upon him was a sword whose hilt was iron—"and in it are the obligatory alms (Zakat)."