The Mu'adhdhin Should Wait For The Imam
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 .
Jabir b. Samurah said: Bilal would call the Adhan, then he used come to wait. When he would see that the prophet (ﷺ) had come out (of his house), he would pronounce the iqama.