Sunan Abu Dawood, Chapter: Prayer (Kitab Al-Salat)

When the adhan for the dawn prayer was initially introduced, the Prophet (peace_be_upon_him) commanded me to call the adhan and I did so. Then I began to ask: Should I utter iqamah, Apostle of Allah? But he began to look at the direction of the east, (waiting) for the break of dawn, and said: No. When the dawn broke, he came down and performed ablution and he then turned to me. In the meantime his Companions joined him. Then Bilal wanted to utter the iqamah, but the Prophet (peace_be_upon_him) said to him: The man of Suda' has called the adhan, and he who calls the adhan utters the iqamah.