Mukhtasar Muslim (Abridged) 193 — Appointing two muadhdhins

Narrated Ibn Umar (may Allah be pleased with them) that the Messenger of Allah (peace and blessings of Allah be upon him) had two muezzins. One was Bilal (may Allah be pleased with him) and the other was Abdullah bin Umm Maktum (may Allah be pleased with him), who was blind.