Sunan Abi Dawud, Hadith 537 ⓘ
Jabir b. Samurah said: Bilal would call the Adhan, then he used come to wait. When he would see that the prophet had come out (of his house), he would pronounce the iqama.
حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا شَبَابَةُ، عَنْ إِسْرَائِيلَ، عَنْ سِمَاكٍ، عَنْ جَابِرِ بْنِ سَمُرَةَ، قَالَ كَانَ بِلاَلٌ يُؤَذِّنُ ثُمَّ يُمْهِلُ فَإِذَا رَأَى النَّبِيَّ صلى الله عليه وسلم قَدْ خَرَجَ أَقَامَ الصَّلاَةَ .
also referenced under: Hadith 537 (DarusSalam) & Book 2, Hadith 537 (USC-MSA)