The Messenger of Allah ﷺ was cupped, and he instructed me to give the cupper his payment.
احتجم رسول الله ﷺ، وأمرني أن أعطي الحجام أجره.
Abu Dawud Tayalisi (148) narrated it from Waraqa, from Abdul-Ala, from Abu Jamila, from Ali, and he related it. Ibn Majah (2163), Ahmad (692), Bayhaqi (9/338), and Tirmidhi in Shamail (355) all narrated it through the route of Abu Dawud Tayalisi. Ibn Majah also narrated it through the route of Yazid bin Harun, from Waraqa, in similar fashion.Abdul-Ala is Ibn Amir Thalabi Kufi, who was judged daif on account of his memory, and for this reason Hafiz said in Taqrib, "Truthful but makes mistakes."He was corroborated by Abu Janab, from Abu Jamila, who said, "I heard Ali say, 'The Messenger of Allah ﷺ was cupped, and when the cupper had finished, he said to him, "How much is your fee?" He said, "Two saa." So he waived one saa for him, and he instructed me, so I gave him one saa.'"Ibn Abu Shayba (6/267) narrated it, and from him Ahmad (1136), from Waki, from Abu Janab, and he related it.Abu Janab is Yahya bin Abu Haya Kalbi, who is daif, but with the combination of the two routes the hadith becomes hasan.Abu Jamila is Maysara bin Yaqub Tahawi Kufi, the bearer of Ali's banner. He explicitly stated that he heard from Ali, which is plausible given his closeness to him from having carried his banner.However, Abdul-Rahman bin Abu Hatim asked his father about a hadith narrated by Hakeem bin Zayd, from Abdul-Ala Thalabi, and he said, "This is a mistake, and the correct version is that Abu Jamila narrated it from the Prophet ﷺ as a mursal report." (Ilal 2/21-322)Perhaps he meant this particular chain, which does not contain an explicit statement of direct hearing, for otherwise Waraqa did narrate from Abdul-Ala, and in some of his routes there is an explicit statement of having heard directly from Ali.