Musnad Ahmad 907:47

Hashim narrated to us, Zuhayr narrated to us, Simak narrated to us, from Jabir ibn Samurah, who said: "Bilal used to call the adhan when the sun passed the meridian. Then he would not perform the iqamah until he saw the Prophet, peace and blessings of Allah be upon him. When he saw him, he would perform the iqamah as soon as he saw him."