Muhammad invented Allah, Islamic Prayers and Zakat (Islamic Tax). Omar invented Azaan, Qibla, Hijab, Sharia, and other khalifs published the Quran and Hadis after the death of Muhammad.
Muhammad’s purpose of inventing of Allah and Islamic Prayers was to organize the Arabs against the Jew and Christians. First, Muhammad declared himself a Prophet, and initiated the prayer rituals. He claimed that angel Jibreel came to him and a spring of water gushed out of the rocks in front of him. Jibreel then showed Muhammad how to make ablution, and how to offer prayers to Allah. Muhammad began to pray two Rak’ah (units) twice a day, once in the morning and once in the evening. He went home and told his wife Khadijah about what he had learnt from Jibreel.
This is story (totally false) told by Muhammad. But one must consider that belief in all kinds of angels was spread all over Arabia. Muhammad simply used, what the people already in belief in, to make up his stories aiming to achieve his goals for attaining power and dominion.
Initially, Muhammad organized prayers twice a day—i.e. morning and evening. Prior to his intended migration to Medina, he invented the story that he was taken on a night journey to Jerusalem and then to the heavens for meeting Allah. His intention was to make his Islam a religion in line with Judaism, since Jews were dominant in Medina and hoped that attaching faith to Jerusalem would help its spread among the Jews of Medina. He also wanted authentication and money (zakat) from the Jews.
Muhammad claimed that during this night journey to the heaven via Jerusalem, Allah (?) ordered him to pray five times a day, following repeated bargaining after Allah’s initial demand of daily 50-time prayers. It was a heavenly gift from Allah to the believers as Muhammad said: "The prayer is the Miraaj (journey to heaven) for the Believer." But to a spiritual believer, doing physical prayers in the name of faith is superstition.
This prayer is nothing but sequence of 8 physical steps: 1) Standing, 2) hands up, 3) hand fold, 4) bend forward, 5) Stand up, 6) prostrate, 7) sit, 8) prostrate-standup. This is one unit (Rak’ah). They do two or four units on five occasions during the course of a day. To Muhammad, this was their gathering and practicing physical drills for organizing them against the non-Muslims. Early Muslims were, thus, a faith-based militia invented by Muhammad. Islam was established and spread thanks to this military organizing system. In the guise of praying to God, Muslims do nothing but physical drills, which helped their military assaults and success against non-Muslims.
The prayers, aka military drills, of Islam have been very useful to tyrant rulers of Arabia and to fanatic clergy over the ages since the days of Muhammad. They get strength (manpower), madness (fanaticism) and money (Zakaat from Muslims; booty & jizya from non-Muslims).
Most Muslims—whether extremist, modern or secular—easily fall in the trap of Mullahs and tyrants, because Islam promises to offer them worldly and after-worldly rewards and success. During azaan, they said “come to success”, “come to success”, “come to success” (three times). Muslims are prone to Islam, a jihadi or militant creed, they hope to get rewards—i.e. entry into Islamic heaven, a brothel run by Allah—after death if die in jihad against non-Muslims. Those, who remain alive, get more women, booty, and zakaat. And they also love the Islamic thought of dominating, oppressing and exploiting non-Muslims, which appeals to an innate human instinct.
In sum, the central purpose of Islamic prayers was to organize Muslims militarily for attaining power, dominion and wealth (booty) and to fulfill their carnal lust as started with Muhammad, and nothing else.