Sunan Abi Dawud 20950
In-book no 446حَدَّثَنَا مُؤَمَّلُ بْنُ الْفَضْلِ، حَدَّثَنَا الْوَلِيدُ، عَنْ حَرِيزٍ، - يَعْنِي ابْنَ عُثْمَانَ - عَنْ يَزِيدَ بْنِ صَالِحٍ، عَنْ ذِي، مِخْبَرِ بْنِ أَخِي النَّجَاشِيِّ فِي هَذَا الْخَبَرِ قَالَ فَأَذَّنَ وَهُوَ غَيْرُ عَجِلٍ .
This tradition has also been transmitted through another chain of narrators by Dhu Mikhbar, the nephew of the Negus. This version adds: "He (Bilal) called for prayer unhurriedly."