(4) باب اسْتِحْبَابِ اتِّخَاذِ مُؤَذِّنَيْنِ لِلْمَسْجِدِ الْوَاحِدِ
Ibn Umar reported:
The Messenger of Allah (ﷺ) had two Mu'adhdhins, Bilal and 'Abdullah b. Umm Maktum, who (latter) was blind.
Reference: Sahih Muslim 380 a
In-book reference: Book 4, Hadith 7
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 741