It is narrated from Nafi‘ that Sayyiduna Abdullah bin Umar (may Allah be pleased with him) said: When the Muslims came to Madinah, they used to gather for prayer by estimating the time; no one used to call the adhan for prayer. One day, the people discussed this matter. Someone suggested making a bell like the Christians’ bell, and some said to make a horn like the Jews’ horn. But Sayyiduna Umar bin Khattab (may Allah be pleased with him) said: Why don’t you send a man to announce the prayer at its time? (Since this opinion was liked,) the Messenger of Allah (peace and blessings be upon him) said: Bilal! Stand up and announce the prayer.