In the early days of the Muslim community in Madinah, the need arose for a way to gather the people for communal prayers. While in Makkah, the Muslims often prayed in secret due to persecution, the newfound freedom in Madinah allowed them to pray openly and required a method to organize the community for prayer times. This led to discussions among the Prophet Muhammad (PBUH) and his companions about how best to summon the faithful.
Various suggestions were put forward, including using a bell like the Christians or a horn like the Jews, but these were not adopted. Instead, a more distinctive and fitting method was sought. According to a narration in Sahih al-Bukhari, the solution came through a vision experienced by Abdullah ibn Zayd, a companion of the Prophet. In this vision, he was taught the words of what would become the adhan, the call to prayer. Upon hearing of this vision, the Prophet approved it and instructed Bilal ibn Rabah, one of the earliest converts to Islam and a former slave, to call the adhan due to his strong and beautiful voice.
Thus, Bilal became the first mu'adhdhin, or caller to prayer, standing on the roof of the Prophet's mosque to deliver the adhan. This marked a significant development in the Muslim community, as the adhan not only served as a practical means to announce prayer times but also reinforced the unity and identity of the Muslims.