Musnad Ahmad 907:201

Aswad ibn Amir narrated to us, Isra'il narrated to us, from Simak, from Jabir ibn Samurah, who said: "The mu'adhdhin of the Prophet, may Allah bless him and grant him peace, would give the adhan, then he would not give the iqamah. He would wait until he saw that the Prophet, may Allah bless him and grant him peace, had come out, then he would give the iqamah for the prayer."