I said, and Musa said in another place that Uthman bin Abu As said, "Messenger of Allah, appoint me as the imam of my people."He said, "You are their imam. Follow the pace of the weakest among them, and appoint a muezzin who does not take payment for his call to prayer."
حدثنا موسى بن إسمعيل حدثنا حماد أخبرنا سعيد الجريري عن أبي العلاء عن مطرف بن عبد الله
قلت وقال موسى في موضع آخر إن عثمان بن أبي العاص قال يا رسول الله اجعلني إمام قومي قال أنت إمامهم واقتد بأضعفهم واتخذ مؤذنا لا يأخذ على أذانه أجرا
[Its chain of transmission is sahih]. Nasai narrated it, in adhan, chapter on employing a muezzin who does not take payment for his adhan, hadith 673, from the hadith of Hammad bin Salama, with this wording. Hakim graded it sahih in 1/199, 201, according to the criterion of Muslim, and Dhahabi agreed with him.