Musnad Abu Ya'la al-Mawsili 164:15

Mu'awiyah ibn Abi Sufyan performed Hajj, and Mu'awiyah ibn Hudayj performed Hajj with him, and he was among those who insulted Ali the most. It was said that he passed through Medina while al-Hasan ibn Ali and a group of his companions were sitting. It was said to him, "This is Mu'awiyah ibn Hudayj, the one who insults Ali." He said, "Bring the man to me." A messenger came to him and said, "Answer him." He said, "Who?" He said, "Al-Hasan ibn Ali calls you." So he came to him and greeted him. Al-Hasan said to him, "Are you Mu'awiyah ibn Hudayj?" He said, "Yes." He repeated that to him. He said, "And you are the one who insults Ali?" It was as if he felt ashamed. Al-Hasan said to him, "As for me, by Allah, if you arrive at the Basin—and I do not think you will arrive at it—you will find him with his lower garment tucked up to his shin, driving away the banners of the hypocrites from it, just as a stranger drives away camels, according to the word of the Truthful, the Believed. And he who fabricates has indeed failed."