Hadith 7

Sahih Muslim

Book 4: The Book of Prayers

Chapter 4

It Is Recommended To Have Two Mu'adhdhin In A Single Masjid

باب اسْتِحْبَابِ اتِّخَاذِ مُؤَذِّنَيْنِ لِلْمَسْجِدِ الْوَاحِدِ ‏‏

Sahih Muslim 380a
حَدَّثَنَا ابْنُ نُمَيْرٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا عُبَيْدُ اللَّهِ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، قَالَ كَانَ لِرَسُولِ اللَّهِ صلى الله عليه وسلم مُؤَذِّنَانِ بِلاَلٌ وَابْنُ أُمِّ مَكْتُومٍ الأَعْمَى ‏.‏
Ibn Umar reported:

The Messenger of Allah (ﷺ) had two Mu'adhdhins, Bilal and 'Abdullah b. Umm Maktum, who (latter) was blind.