Musnad Ahmad 5:398

Yahya ibn Adam narrated to us, Sharik narrated to us, from Mikhariq, from Tariq ibn Shihab, who said: I saw Ali on the pulpit delivering a sermon, and upon him was a sword whose ornamentation was iron. I heard him say: "By Allah, we have no book that we read to you except the Book of Allah the Exalted, and this scroll which the Messenger of Allah, may Allah bless him and grant him peace, gave to me, in which are the obligatory duties of charity." He said: "The scroll was hanging from his sword."