The adhan is the call given to announce that it is time for a particular obligatory Salah (ritual Prayer). Five times a day the adhan is raised from mosques throughout the world. It is a Sunnah (optional duty) that brings its own reward from Allah (God). The person who gives the adhan is called a muadhdhin. (The English word “muezzin” is a mispronunciation of the Arabic term.)
The adhan begins with an affirmation of the supremacy of Allah (God). Then comes the shahadah (profession of faith), which consists of the profession of the Unity of Allah (God), the negation of Shirk (polytheism), and the confirmation that Muhammad (peace and Blessings be on him) is the Messenger of Allah (God). And after that, comes the call to the Prayer and to success — our eternal home in Paradise — which also implies our return to the Creator. Each line is repeated for emphasis.