Sahih al-Bukhari 607
صحيح البخاري#607Sahihحَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا خَالِدٌ، عَنْ أَبِي قِلاَبَةَ، عَنْ أَنَسٍ، قَالَ أُمِرَ بِلاَلٌ أَنْ يَشْفَعَ، الأَذَانَ، وَأَنْ يُوتِرَ الإِقَامَةَ. قَالَ إِسْمَاعِيلُ فَذَكَرْتُ لأَيُّوبَ فَقَالَ إِلاَّ الإِقَامَةَ.
Narrated Abu Qilaba:Anas said, "Bilal was ordered to pronounce the wording of Adhan twice and of Iqama once only." The sub narrator Isma`il said, "I mentioned that to Aiyub and he added (to that), "Except Iqama (i.e. Qad-qamat-is-salat which should be said twice)
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 10:5