The takbir is the exclamation Allahu akbar, God is greater (or greatest), the most frequently pronounced formula in Muslim worship. It opens the ritual prayer and marks each change of posture within it, sounds in the call to prayer, and is repeated at the festivals, on the pilgrimage, and at moments of joy, wonder, danger and grief. Its meaning sets the greatness of God above every other thing to which the mind might turn, and its constant recurrence threads that recognition through the acts of worship and the ordinary occasions of life alike. As dhikr it is repeated in remembrance of God, and it is among the phrases used to glorify God after the obligatory prayers. The takbir is thus at once a liturgical marker, a festal cry and a personal act of devotion, and few formulas are so woven into the daily texture of Muslim life.
Grammatically the phrase is built from akbar, a comparative form of kabir, great, with no stated object of comparison, which classical commentary treats as deliberate: God is declared greater than anything the speaker could name, so supplying an object would narrow the claim. The takbir's use to mark ritual transitions gives Islamic prayer an audible structure independent of language, since a worshipper who does not understand Arabic can still follow the prayer's movement, standing, bowing, prostrating, by ear alone. Historically the cry has also carried a martial and political register, used on the battlefield and at moments of public assertion, separate from its constant devotional repetition in ordinary worship.