"WHY WAS THE LAST PROPHET NEEDED?
Arabs: Islam's major sin is denying Allah. There are two common ways to deny Allah: by substituting idols for Allah or by being self-sufficient and ignoring Allah. Arabs were guilty of idol worship and self-sufficiency. Pre-Islamic Arab monotheists, called Hanifs, were descendants of Abraham and his son Ishmael. With centuries, the Arabs, like others, followed the downward slope from monotheism to idolatry. Idol worship has a close association with sexual immorality, human sacrifice, and greed in all forms. Before Muhammad's prophethood, Allah sent prophets like Hud, Salih, Jethro, Job, etc., to reform Arabs, but to no avail.
Jews are considered the ""chosen people"" for being the first to adopt monotheism. The Torah gave the Jews an illusory feeling of superiority as they were the sole recipients of Allah's revelation. Due to their illustrious ancestors like Abraham, Isaac and Jacob, the spiritual concept of "chosen people" morphed into a supremacist ideology or inherited form of "chosen people." Since they think they occupy a privileged position in Allah's sight, Jews do not see the need to share revelations with inferior gentiles. They failed to propagate monotheism. Moreover, they rejected Jesus who was sent to reform children of Israel.
Christians: Jesus himself was a practicing Jew and a strict monotheist. Christians fell into the same trap of idolatry by elevating Jesus to Allah and worshipping a human being. Paul declared Torah laws no longer binding on Christians blurring the line between sin and morality. Augustine invented free salvation. It is enough for salvation to believe that Jesus died on the cross and paid for humanity's sins. This deprives sinners of the incentive to reform themselves and evolve into better persons. As a result, you earn salvation through Allah's grace and good works that benefit humanity. The last Prophet was needed to correct the errors of pagan Arabs and followers of earlier revelations.
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