Musnad Ahmad 32:1456

Yunus and Ishaq ibn Isa narrated to us, they said: Hammad ibn Salamah narrated to us, from Ali ibn Zayd, from Anas ibn Malik, that he said: The King of Rome gifted the Prophet, may Allah bless him and grant him peace, a garment of silk brocade (*sundus*), and he wore it. It is as if I am looking at its sleeves dangling because of their length. The people began saying: "O Messenger of Allah, was this sent down to you from the heaven?" He said: "What amazes you about it? By the One in Whose hand is my soul, indeed a handkerchief from the handkerchiefs of Sa'd ibn Mu'adh in Paradise is better than it." Then he sent it to Ja'far ibn Abi Talib, and he wore it. The Prophet, may Allah bless him and grant him peace, said: "I did not give it to you so that you would wear it." He said: "Then what should I do with it?" He said: "Send it to your brother, the Negus."