Ubaydullah bin Abu Rafi reported,

When the Haruriyyah went out in revolt, he was with Ali bin Abu Talib . They said, "Judgment belongs to Allah alone."Ali said, "A true word by which falsehood is intended. The Messenger of Allah ﷺ described certain people, and I recognize their description in these men. They speak the truth with their tongues, but it does not pass beyond this of them," and he pointed to his throat. "Among the most hateful of Allah's creation to Him is a black man among them, one of whose hands is like the teat of a goat or the nipple of a breast."When Ali bin Abu Talib had killed them, he said, "Look for him."They looked but found nothing, so he said, "Go back and look. By Allah, I have not lied, nor was I lied to," saying this two or three times. Then they found him in a ruin, and they brought him and laid him before Ali.Ubaydullah said, "I was present for that affair of theirs and for what Ali said about them."Yunus added in his narration that Bukayr said, "A man told me, on the authority of Ibn Hunayn, that he said, 'I saw that black man.'"

حدثني أبو الطاهر ويونس بن عبد الأعلى قالا أخبرنا عبد الله بن وهب أخبرني عمرو بن الحارث عن بكير بن الأشج عن بسر بن سعيد

عن عبيد الله بن أبي رافع مولى رسول الله ﷺ

أن الحرورية لما خرجت وهو مع علي بن أبي طالب رضي الله عنه قالوا لا حكم إلا لله قال علي كلمة حق أريد بها باطل إن رسول الله ﷺ وصف ناسا إني لأعرف صفتهم في هؤلاء يقولون الحق بألسنتهم لا يجوز هذا منهم وأشار إلى حلقه من أبغض خلق الله إليه منهم أسود إحدى يديه طبي شاة أو حلمة ثدي فلما قتلهم علي بن أبي طالب رضي الله عنه قال انظروا فنظروا فلم يجدوا شيئا فقال ارجعوا فوالله ما كذبت ولا كذبت مرتين أو ثلاثا ثم وجدوه في خربة فأتوا به حتى وضعوه بين يديه قال عبيد الله وأنا حاضر ذلك من أمرهم وقول علي فيهم زاد يونس في روايته قال بكير وحدثني رجل عن ابن حنين أنه قال رأيت ذلك الأسود