Sunan Ibn Majah 731
سنن ابن ماجه#731Sahihحَدَّثَنَا هِشَامُ بْنُ عَمَّارٍ، حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ سَعْدِ بْنِ عَمَّارِ بْنِ سَعْدٍ، مُؤَذِّنِ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ حَدَّثَنِي أَبِي عَنْ أَبِيهِ عَنْ جَدِّهِ أَنَّ أَذَانَ بِلاَلٍ كَانَ مَثْنَى مَثْنَى وَإِقَامَتُهُ مُفْرَدَةً .
Abdur-Rahman bin Sa'd bin 'Ammar bin Sa'd narrated (from his great-grandfather of the Messenger of Allah) that:In the Adhan of Bilal, the phrases were two by two, and in his Iqamah they were said once
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:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Shuaib Al ArnautSahih Lighairihi
Zubair Ali ZaiDaif
In-book reference: 3:26