The theology of the Holy Qur'an primarily emphasizes the Unity of God; and its first message is "there is no God beside Allah"; this message has been repeated more than sixty times in the Holy Qur'an. The prophet's first words are monotheism and sincerity. "Ahad" (the One) refers to the unity of the Most High God from the viewpoint of Ontology. "Tohid" (monotheism) is considered as the borderline between faith and disbelief; and a person is considered "Movahed" (monotheist) only if he believes in it. The present article is an attempt to analyze and clarify these concepts.
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