(1) باب
Narrated Ali ibn AbuTalib:
The Prophet (ﷺ) said: A man called al-Harith ibn Harrath will come forth from Ma Wara an-Nahr. His army will be led by a man called Mansur who will establish or consolidate things for Muhammad's family as Quraysh consolidated them for the Messenger of Allah (ﷺ). Every believer must help him, or he said: respond to his sermons.
Reference: Sunan Abi Dawud 4290 b
In-book reference: Book 38, Hadith 13
English translation: Book 37, Hadith 4277