Abu Dawud Book 27, Hadith Number 4026.

Narated By Abdullah ibn Abbas : When the Haruriyyah made a revolt, I came to Ali (may Allah be pleased with him). He said: Go to these people. I then put on the best suit of the Yemen.

Abu Zumayl (a transmitter) said: Ibn Abbas was handsome and of imposing countenance. Ibn Abbas said: I then came to them and they said: Welcome to you, Ibn Abbas! what is this suit of clothes? I said: Why are you objecting to me? I saw over the Apostle of Allah (PBUH) the best suit of clothes.

Abu Dawud said: The name of Abu Zumail is Sammak b. al-Walid al-Hanafi.