Sunan Abi Dawud 531
سنن أبي داود#531SahihNarrated Uthman ibn Abul'As: Messenger of Allah, appoint me the leader of the tribe in prayer. He said: You are their leader, but you should follow on who is the weakest of them: and appoint a mu'adhdhin who does not charge for the calling of adhan
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 2:141