For I am God, and there is no one else; I am God, and there is no one like me. — Isaiah 46:9
Monotheism is the belief that there is only one God. That is true and of great importance. However, monotheism is an insufficient truth. People may believe that there is one God but have the wrong one in mind. It is a weakness of the term monotheism that while it tells us there is only one God, it does not in itself identify who that God is.
It is not the concept of monotheism that animates God’s prophets of old. To them, it would not matter whether people believed in one god or not, if that one God is not YHWH. It is him that they celebrate. He is their Father (Deut. 32:6). Their monotheism is incidental to the eternal truth that he alone is God. Original monotheism is by definition about “the LORD.”
God’s First Priority
To God, the most essential of all truths is the truth about himself. Who he is and his sovereignty are the center of all that is right. He proclaims in the Scripture above, “I am God, and there is no one else; I am God, and there is no one like me.” YHWH’s first priority is not that human beings would know that there is only one God. His first priority is that all would know that he is God — he alone.
That priority is at the heart of God’s relationship with people. How can human beings have a meaningful relationship with him if they do not know clearly who he is? Without the understanding that only he is God, they will search in vain to find truth elsewhere. They will not know to whom they should look for help; to whom they should give thanks. Without that understanding, all is futile; all is lost. The first priority is so essential, so fundamental, that all understanding of God must be measured by it. All right understanding of Scripture conforms to it. And for his people in the Bible, it goes beyond factual correctness. To know the one who alone is God is a matter of privilege. It is a tremendous honor that he is their God.
God’s Prime Directive
You shall have no other gods before me (Ex. 20:3). The Ten Commandments do not begin on a moral or ethical note as such. Rather, the first order of business in the commandments is related to God’s sovereignty: They shall have no other gods before him. The eternal truth that “he alone is God” now takes the shape of this crucial directive to the people: They shall serve him as God and no one else (Deut. 6:13; 10:20).
To the people of the Bible, that decree is critical. If they keep all of the commandments but violate this one, keeping the others has little value. “He alone is God” is the principle upon which their faith and lives are built. That they are to serve only him as God is his most essential directive to the people. It is impossible to keep the first commandment while acknowledging anyone as God other than him.
Original monotheism was more than just a concept or ideal. It brought people to an unambiguous dedication to only one individual as God. That one was the LORD. While ancient Israel is often recognized as forwarding the cause of monotheism, that recognition by itself falls short. The nation’s unique gift to the world was actually YHWH himself:
So know this today, and take to heart, that the LORD, he is God in heaven above and on the earth below; there is no one else. Obey his statutes and commands which I am giving you today (Deut. 4:39, 40).
Gill, J. Dan (2016). Monotheism – An Insufficient Truth. In, The One: In Defense of God (pp. 87-89). Nashville, TN: 21st Century Reformation Publishing.
 The word monotheism is derived from the Greek terms monos (only, alone) and theos (God). Both words occur in John 17:3.
 It is interesting that the foundation of faith for the people of the Bible is not monotheism as such. The point of the Scriptures is that YHWH is God and the only one who is.
 “Before me.” The reference is not to priority. Rather, they shall have no other gods in his presence (paniym — before his face).
 Jesus quotes Deuteronomy 6:13 and obeys that same command himself (Matt. 4:10; Luke 4:8).