Allah commands His servants to say "Allaah is the Greatest". Though soft on the tongue, it's heavy on the scale of reward.
The article covers the essence of five daily obligatory prayers in the life of Human being and its objectives.
The spirit of salah is intention, devotion, and contemplation. Without contemplation, invocation is of no avail since this will be futile utterance.
Physical purity means cleanliness of the body, clothing and environment. Muslims must have perfect physical purity to pray the Salah.
The minaret of a mosque used to be the place from which the muezzin would call out for prayers. 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