The Adhan is the call to prayer, pronounced aloud before each of the five daily prayers, traditionally from the minaret of the mosque and now often amplified. Its lines are short declarative statements of the faith: the greatness of God (Allahu akbar), the two testimonies that there is no god but God and that Muhammad is His messenger, the summons to prayer and to well-being, and, before the dawn prayer, the added line that prayer is better than sleep. The tradition holds that the call was instituted at Medina in the first years of the community, and it attributes its first performance to Bilal ibn Rabah, a freed Abyssinian slave chosen for his voice, a figure Muslims remember with particular affection.
The adhan is not scripture but transmitted practice, and its wording differs slightly between the Sunni schools and the Shia, whose call adds a line on the authority of Ali. As sound it has become one of the defining features of Muslim life, marking the hours over cities and villages five times a day, and its recitation is an art in its own right, the muezzin's melodic delivery a valued skill. Answered by the shorter second call (iqama) that immediately precedes the prayer itself, the adhan turns the measurement of the day into a continual public proclamation of the faith.