I believe that the phrase "God is One" is often subject to misinterpretation and here is why.
Islamic Belief: Muslims have faith in Allah as the sole, all-powerful God, the Sovereign and the Creator. They place their trust and fear solely in Him.
Jewish Belief: Jews uphold the belief in a singular, incomparable God.
Christian Belief: Christians adhere to the belief in only one God, as stated in Isaiah 43:10; 44:6, 8; John 17:3; 1 Corinthians 8:5-6; Galatians 4:8-9. Christianity, however, introduces the Trinity concept, sparking considerable debate and conflict with other faiths. The Trinity denotes the triune nature of God: Father, Son, and Holy Spirit, as referenced in Matthew 3:16-17, 28:19; John 14:16-17; 2 Corinthians 13:14; Acts 2:32-33; John 10:30, 17:11, 21; 1 Peter 1:2.
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This notion has even led to confusion among Christians themselves.
Islam, Judaism, and Christianity all profess belief in a singular God. Yet, in the creation narratives of the Quran, Tanakh, and Bible, God is frequently mentioned using plural pronouns (WE, US, OUR). It would arguably be more logical to use singular pronouns (I, ME, MY) to underscore God's singularity. This is the basis for my view that the statement "God is One" is not fully understood.
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Examples:
Islam: The Quran quotes God: "Indeed, We created man from a mingled sperm-drop, to test him; thus, We gave him hearing and sight. His procreation stems from various elements, fitting his multifaceted role in the universe, necessitating a broad spectrum of attributes. Does man not recall that We created him previously when he was nothing? (19:68) And We made every living thing from water... (21:31) Did We not create you from a trivial fluid, which We placed in a secure environment? (77:22)" (21 The Prophets - al-Anbiya)
> "Do the disbelievers not see that the heavens and the earth were one mass, and We tore them apart? And We made from water every living thing. Will they not believe? And We placed on earth stabilizers, lest it sways with them, and We placed therein signposts and passages, that they may be guided. And We made the sky a protected ceiling; yet they turn away from its wonders. It is He who created the night and the day, and the sun and the moon; each floating in an orbit. We did not grant immortality to any human being before you. Should you die, are they then the immortal? Every soul will taste death. We burden you with adversity and prosperity—a test. And to Us you will be returned." (21:30-35)
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In Judaism, the Tanakh says: "And God said, 'Let us make man in our image, after our likeness; and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creeps upon the earth.' And God created man in His own image, in the image of God He created him; male and female He created them." (Genesis 1:26-27)
"And the LORD God said, 'Behold, the man has become like one of us, knowing good and evil; now, lest he reach out his hand and take also from the tree of life, and eat, and live forever.'" (Genesis 3:22)
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In Christianity, the Old Testament (similar to the Tanakh) states: "Then God said, 'Let Us make man in Our image, according to Our likeness; let them have dominion over the fish of the sea, over the birds of the sky, over the cattle, over all the earth, and over every creeping thing that creeps on the earth.' God created man in His own image, in the image of God He created him; male and female He created them." (Genesis 1:26-27)
"The Lord God said, 'The human has now become like one of us, knowing good and evil. Now, so that he does not reach out his hand and take also from the tree of life, and eat, and live forever.'" (Genesis 3:22)
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The true meaning of "ONE" and "GOD IS ONE" can be further understood through the words of Jesus (Yeshua).
First, Jesus stated that He existed with the Father before the world was created, which explains the plural form of God in creation: "Now, Father, glorify me in your presence with the glory I had with you before the world was created." (John 17:5)
Jesus also declared that He and the Father are One: "I am no longer in the world, but they are in the world, and I am coming to you. Holy Father, protect them in your name that you have given me, so that they may be one as we are one." (John 17:11)
When we accept Jesus into our lives and receive the Holy Spirit, we become one with Christ: > "We have many parts in one body, but the parts don’t all have the same function. In the same way, though there are many of us, we are one body in Christ, and individually we belong to each other." (Romans 12:4-5)
Another way to understand “God is One” is to see God like we see a man and a woman who, through marriage, become one.