Salah in Islam is a special prayer which is informed to the Prophet Mohammad (S.A.W.) through revelation and its boundaries and form are determined. Any change in its form nullifies it. Salah is a discipline which is set as a binding duty for all Muslims as it is formal. Islam targeted to discipline its members and saved the endless conscious of the existence of Allah by setting it as a binding duty for Muslims. Salah train a Muslim for a healthy and well-organized life by dividing the day into intervals. It is accepted as refreshing and cleaning practice with abdast (ritual ablution) performed by clean water.
It works as a work-out for body as well by the postural changes between standing, kneeling, prostrating and sitting. Salah brings physical and psychological serenity and spiritual pleasure with itself. It is taking the mind from the daily works to concentrate Allah, his decrees and his existence, and raise you to the absolute and universal sovereignty. The one who worship comes out to face with this life and its problems more ready than before. The true nature of Salah, the ideas coming with the religious sentence, makes the person eager; it directs the one to beneficial works; it strengthens its determination to avoid wickedness and to fill the world with goodness. And finally, when it is performed together with a community, it induces Muslims, at the same lines, for equality, universality, brotherhood and to care about one’s brothers/sister (*).

All creatures in the universe, including the sun, meadow, grass, trees, perform dhikr all the time. The nature of birds flying as a flock, mountains, stones serve for Allah in a way that is unknown for us. They all perform their prayers in their way, the plants in standing, animals in bowing, and the inorganic objects in prostrating. The sky domestics are in the same situation.

Some part of the angels performs it in bowing while some others in prostrating or telling his name (tespih) and Tehlil… However, Salah, as a prayer, is prayer having all worships in its structure. Therefore, the real performers of Salah carry out a worship containing all worships of the creatures in the ground and the sky.

The Prophet (S.A.W) ordered that: Salah gives consent of Allah who is sublime and great. It provides the love of angels. It is the way of the Prophet. It is the light of talent and the basis of faith. It is an instrument for acceptance of prayer. It makes actions accepted. It provides fruitfulness for foods and relaxation for body. It is a weapon on enemies. It keeps the Satan away. It is an interceder between the death and the Angel of Death. It is a light and a ground cloth in the grave. It is the answer for the questions of Munker and Nekir. It is like a congenial companion in the grave till the Apocalypse. It is a shady spot on the ones who performed Salah in the Apocalypse. It is a crown for one’s head. It is a dress for one’s body. It is the light going in front of the one. It is a curtain put between the human beings. It is the evident of believers in the presence of their Lord. It is heaviness in the divine balance. It is a passage to the Sirat. It is a key to the Heaven. Because Salah is tespih, praise, respect, reading, and prayer. Consequently, all of the good performances are contained in Salah performed on its time. (Tenbîhi’l-Gafilîn, 293)

How Salah became a binding duty?
Duties were informed to Hazrat Mohammad (Sallalahu Alayhi Wa salaam) through Archangel Gabrail. But Salah five times a day is, apart from all these, given to the Lord of the Worlds by Allah, Himself, as a present on the night of Miraaj. Salah which was became a binding duty as 50 times a day at the beginning, was reduced to 5 times a day finally, with the 5 requisitions and begging of the Prophet of Allah to Allah on the night of Miraaj, by this advice of Hazrat Moses (Alayhi Salaam) to Hazrat Mohammad (Sallalahu Alayhi Wa salaam) in the sky:

Oh, the Prophet of Allah! I had experienced with the boys of Israel before. Your community will not be able to perform for fifty times!
After it was finally decided as five times a day, Hazrat Moses again told our Prophet (Sallalahu Alayhi Wa salaam) that:

They can not be able to perform this.
But our Prophet (Sallalahu Alayhi Wa salaam) said that:

I am ashamed to require more than this from Allah.
And, He had chosen five times a day as the final. But Allah gave this joyful news along with the reduction to the Prophet Allah that: “Oh my Prophet! The word is never changed in my presence. You will take the benefit of fifty times of Salah in return of performing five times a day of Salah” (İbn-i Mace, İkameti’s salat, 194) on the night, as the union night.
Hazrat Mohammad (Sallalahu Alayhi Wa salaam) tells His community on the matter of five times: “Allah ordered that; “I put five times a day of Salah as a binding duty on your community. There is a promise given in my presence. I will surely put the ones in the Heaven who performs these Salahs on time. But, there is no promise given in my presence for the ones who do not protect these salahs.” ” (İbn-i Mace, İkameta’s salat, 194)