Musannaf Ibn Abi Shayba 27:557

Muttalib ibn Ziyad narrated to us, from Jabir, from Abu Ja'far, who said: The Messenger of Allah (peace and blessings of Allah be upon him) passed by a gathering of the Ansar while he was carrying al-Hasan and al-Husayn. They said, "O Messenger of Allah, what an excellent mount!" He said, "And what excellent riders."