The muezzin calls the adhan, the summons to the five daily prayers, and the office is defined by voice, knowledge of the times, and reliability.
Calling the adhan
The muezzin proclaims the call to prayer from the mosque five times a day at the appointed hours, and the office requires a clear and strong voice, an accurate knowledge of the prayer times, which shift with the sun through the year, and the reliability to sound the call faithfully, since the community orders its worship by it. The words of the adhan are fixed, declaring the greatness of God, the confession of faith, and the summons to prayer and to success, and the beauty and clarity of the calling are prized.
An honoured but unordained role
There is no ordination and no clerical caste in the Sunni tradition, so the muezzin holds an honoured function rather than a sacred order, appointed by the mosque, and the office carries a particular dignity from the tradition that the first muezzin was Bilal, a freed Ethiopian slave and Companion of the Prophet chosen for the strength and beauty of his voice, which sets a precedent that the call belongs to merit rather than to birth. In the modern period the call is often amplified or broadcast, and in the great mosques a skilled muezzin remains a valued figure. The office has no exact parallel in traditions that summon worship by bell rather than by the human voice.