The most fundamental teaching of Islam is to believe in the Oneness of God, in the sense of His being the only Creator, Preserver, Nourisher, etc. But this belief is not enough. Many of the idolaters knew and believed that only the Supreme God could do all this and yet they associated other gods with Him. Therefore, one must acknowledge the fact that it is God alone who deserves to be worshipped, and thus abstain from worshipping any other thing or being. Likewise, Muslims believe that God has no father or mother, no son or daughter. None is equal to Him. He is God of all humankind, not of a special tribe or race.
Worship of God alone and no one else
The Quran, the holy book of Islam, reminds us of the falsity of all alleged gods. To the worshippers of man-made objects, it asks: ‘How can you worship things you carve with your own hands, when it is God who has created you and all your handiwork?’ (37:95-96)
At another point, God says, “Say, ‘Why do you take protectors other than Him, who can neither benefit nor harm even themselves?’ Say, ‘Are the blind equal to those who can see? And are the depths of darkness equal to the light?’ Have the partners they assign to God created anything like His creation so that their creation is indistinguishable from His? Say,‘God is the Creator of all things: He is the One, the All Compelling.’” (13:16)
To the worshippers of heavenly bodies the Quran cites the story of Abraham: “When the night grew dark over him he saw a star and said, ‘This is my Lord,’ but when it set, he said, ‘I do not like things that set.’ And when he saw the moon rising he said, ‘This is my Lord,’ but when it too set, he said, ‘If my Lord does not guide me, I shall be one of those who go astray.’ Then he saw the sun rising and cried, ‘This is my Lord! This is greater.’ But when the sun set, he said, ‘My people, I disown all that you worship beside God. I have turned my face as a true believer towards Him who created the heavens and the earth. I am not one of the polytheists.’” (6:76-79)