He said, "Messenger of Allah, appoint me as the imam of my people."The Prophet ﷺ replied, "You are their imam. Follow the pace of the weakest among them, and take a muezzin who does not charge a fee for his call to prayer."
يا رسول الله! اجعلني إمام قومي، قال: أنت إمامهم، واقتد بأضعفهم، واتخذ مؤذنا لا يأخذ على أذانه أجرا.
Abu Dawud (531) and Nasai (672) both narrated it through the route of Hammad bin Salama, who said, Saeed Jareeri narrated to us, from Abu Ala, from Mutarrif bin Abdullah, from Uthman bin Abu As, who related it. From this same route it was also narrated by Ibn Khuzayma (423) and Hakim (1/199–200), who said, "Sahih according to the criterion of Muslim." I say, it is as he said. Saeed Jareeri is Ibn Iyas Abu Masud Basri, who is trustworthy, except that his memory became confused three years before his death, and Hammad bin Salama is among those who heard from him before that confusion set in.Tirmidhi (209) narrated it through another route, saying, Hannad narrated to us, Abu Zubayd, who is Abthar bin Qasim, narrated to us, from Ashath, from Hasan Basri, from Uthman bin Abu As, who said, "Among the last things the Messenger of Allah ﷺ instructed me was to take a muadhin who would not take payment for his adhan." Ibn Majah (714) narrated it through the route of Hafs bin Ghiyath, from Ashath, in a similar wording.Tirmidhi said, "A hasan hadith," and in one copy, "hasan sahih." What Zaylai and others transmitted from him is "hasan" only, and that is correct, for Ashath is Ibn Sawwar Kindi Najjar, whom Nasai, Daraqutni, and others declared daif. Some scholars of knowledge said that he is rather Ibn Abdul-Malik Hamrani, who is trustworthy and a jurist, but the correct view is the first one. The chain also contains Hasan Basri, who practiced tadlis and narrated this with an ambiguous form of transmission ("an"), although his hearing from Uthman bin Abu As has been established, as Bazzar stated. See Nasb Raya (1/90).Based on this hadith, the Hanafis held the view that taking payment for calling the adhan is forbidden. Most scholars of knowledge, however, hold that what is forbidden is only when the adhan is made conditional upon payment, but if payment is given without it being demanded, there is no harm in that, such as when the matter is customarily understood between the muadhins and the Islamic institution. Hence Shafii said, "If the imam grants the muadhin a stipend from the treasury, from the fifth of the fifth of the spoils of war or from the Messenger of Allah's ﷺ share of the fay, there is no harm in that, so long as no volunteer can be found." As for Malik, he permitted it without restriction. Sharh al-Sunnah by Baghawi (2/281).