The Messenger of Allah (ﷺ) had two Mu'adhdhins, Bilal and 'Abdullah b. Umm Maktum, who (latter) was blind.
لِرَسُولِ اللَّهِ صلى الله عليه وسلم مُؤَذِّنَانِ بِلاَلٌ وَابْنُ أُمِّ مَكْتُومٍ الأَعْمَى
The Azan and Iqaamah
284 hadith on this topic, one card per hadith and its versions; authentic ones first. 190 are translated into English.
لِرَسُولِ اللَّهِ صلى الله عليه وسلم مُؤَذِّنَانِ بِلاَلٌ وَابْنُ أُمِّ مَكْتُومٍ الأَعْمَى
‘Abdullāh ibn ‘Umar (may Allah be pleased with him) reported that Bilāl made a call to prayer before the break of dawn. The Prophet (may Allah's peace and blessings be upon him) therefore commanded him to return and make a call: "Lo! The slave of Allah slept. Lo! The slave of Allah slept."
أَلاَ إِنَّ الْعَبْدَ قَدْ نَامَ أَلاَ إِنَّ الْعَبْدَ قَدْ نَامَ " . زَادَ مُوسَى فَرَجَعَ فَنَادَى أَلاَ إِنَّ الْعَبْدَ نَامَ .
" إِنَّ اللَّهَ وَمَلاَئِكَتَهُ يُصَلُّونَ عَلَى الصَّفِّ الْمُقَدَّمِ وَالْمُؤَذِّنُ يُغْفَرُ لَهُ بِمَدِّ صَوْتِهِ وَيُصَدِّقُهُ مَنْ سَمِعَهُ مِنْ رَطْبٍ وَيَابِسٍ وَلَهُ مِثْلُ أَجْرِ مَنْ صَلَّى مَعَهُ "