ʿAmr ibn Shamir transmits—through Jābir al-Juʿfī, from al-Shaʿbī (or, according to another route, from Abū Jaʿfar)—that:

When Muʿāwiyah’s position became dominant, ʿAlī summoned a man and instructed him to ride to Damascus, tether his mount at the mosque gate, and enter still clad in the garb of a traveller. The man did exactly as he had been told.

The people of Syria asked him, “Where are you from?”
He replied, “From Iraq.”
They said, “And what news do you bring?”
He answered, “I have left ʿAlī after he has marshalled his forces against you and roused the Iraqis.”

When this report reached Muʿāwiyah, he dispatched Abū al-Aʿwar to verify the matter (1). Abū al-Aʿwar returned, confirmed it, and a herald proclaimed, “The prayer is in congregation!”

The mosque filled. Muʿāwiyah mounted the pulpit, pronounced the shahādah, and said, “ʿAlī has advanced against you; what is your counsel?”

The people lowered their chins to their chests; no one even lifted his gaze toward him. Then Dhu’l-Kalāʿ al-Himyarī rose and said, “The counsel is yours, and the action is ours”—meaning: we will carry it out.

Muʿāwiyah descended, and a proclamation was made: “Whoever stays away from the camp after three days has brought ruin upon himself.”

Meanwhile, ʿAlī’s envoy returned, related what had happened, and ʿAlī ordered that the call be given: “The prayer is in congregation!”

When the people gathered, he ascended the pulpit and said, “My messenger has arrived and informed me that Muʿāwiyah has advanced against you; what is your counsel?”

The mosque erupted, everyone shouting, “The plan is this,” “The plan is that,” until the sheer volume of voices left ʿAlī unable to discern anything. He stepped down saying, “We belong to Allah and to Him we shall return. The son of the liver-eater has carried the day!” (2)

Al-Aʿmash relates—from someone who saw ʿAlī on the Day of Ṣiffīn—that he was clapping his hands together, biting them, and saying, “How astonishing! I am disobeyed while Muʿāwiyah is obeyed!” (3)