It was narrated that 'Uthman bin Abi Al-As said:
"I said: 'O Messenger of Allah, made me the Imam of my people.' He said: 'You are their Imam, so consider the weakest among them and choose a Mu'adhdhin who does not accept any payment for his Adhan.'" (FR)
English reference (FR): Vol. 1, Book 7, Hadith 673 (FR)
Arabic reference (FR): Book 7, Hadith 680 (FR)