Musnad Ahmad 962:22

Muhammad ibn al-Hasan ibn Atash narrated to us, Ja’far—meaning ibn Sulayman—narrated to us, from Mu’alla—meaning ibn Ziyad—from Abu Ghalib, from Abu Umamah. And (in another chain) Rawh narrated to us, Hammad narrated to us, from Abu Ghalib, from Abu Umamah, who said: A man came to the Messenger of Allah (peace and blessings of Allah be upon him) while he was stoning the Jamrah and said: "O Messenger of Allah, which Jihad is most beloved to Allah?" He remained silent toward him until, when he had stoned the second one, he approached him and said: "O Messenger of Allah, which Jihad is most beloved to Allah?" He remained silent toward him. Then the Messenger of Allah (peace and blessings of Allah be upon him) proceeded until, when he reached the third Jamrah, he approached him and said: "O Messenger of Allah, which Jihad is most beloved to Allah?" He said: "A word of truth spoken to a tyrannical leader." Muhammad ibn al-Hasan said in his narration: And al-Hasan used to say: "To an oppressive leader."