Hadith 154:8
Yahya ibn Adam narrated to us, he said: Ibn Idris and Abu Shihab narrated to us, from Muhammad ibn Ishaq, from al-Zuhri, from al-Sa’ib ibn Yazid, the nephew of Nimr, who said: "The Messenger of Allah, may Allah bless him and grant him peace, had no more than one mu'adhdhin (caller to prayer) who would call the adhan when he sat on the minbar, and would perform the iqamah when he descended." And Abu Bakr was likewise, and Umar was likewise, may Allah be pleased with them both.
حدثنا يحيى بن آدم، قال: حدثنا ابن إدريس، وأبو شهاب، عن محمد بن إسحاق، عن الزهري، عن السائب بن يزيد ابن أخت نمر، قال: " ما كان لرسول الله صلى الله عليه وسلم، إلا مؤذن واحد يؤذن، إذا قعد على المنبر ويقيم، إذا نزل " وأبو بكر كذلك وعمر كذلك رضي الله عنهما