God is one. There is only one person who is God. Before the universe came into being, the living, personal, self-existent God was alone. This one infinite and perfect Being is unique. He has no identical. He is in a class of His own. In His nature, personality, and attributes God is undivided and indivisible.
The unity of God includes two primary thoughts: the oneness of God and the unity of God's character. The oneness of God refers to the fact that there is only one person in the universe who is the supreme source and ruler of all things. The unity of God's character refers to the truth that His nature is undivided.
Christianity is based on monotheism. The God of the Old Testament is the Father of our Lord Jesus Christ. Christianity in the Roman Empire constantly conflicted with paganism. The unity of God naturally became a fundamental doctrine of the apostolic church. Wherever they went, the early missionaries of the church proclaimed the truth of God's oneness. Their converts "turned to God from idols to serve the living and true God" (1 Thess. 1:9).
In writing to the church in the idolatrous city of Corinth, Paul asserted: "We know that an idol is nothing in the world, and that there is none other God but one. For though there be that are called gods, whether in heaven or in earth, (as there be gods many, and lords many,) but to us there is but one God, the Father, of whom are all things, and we in him; and one Lord Jesus Christ, by whom are all things, and we by him" (1 Cor. 8:4-6).
"For there is one God, and one mediator between God and men, the man Christ Jesus; who gave himself a ransom for all, to be testified in due time" (1 Tim. 2:5, 6).
There is one God, one human race, and one mediator between the two. The one God is a unity who alone is the source of all created things. His character is holiness, love, and truth. The one human race has descended from its common ancestors, Adam and Eve. The human race had a common origin and constitutes a unity. The entire human race is in sin and needs salvation. The one mediator is Jesus Christ, the only begotten Son of God.
I. Major Bible Truth
The fact that there is only one God is an outstanding teaching in the Bible. It was the basic message of the prophets and apostles. It is the foundation truth of the gospel.
1. One God. The Bible clearly states that there is one God. Bible writers show that God is a sole individual, a unique being. God is one; there is one person who is God.
Ephesians 4:6 - One God and Father of all
1 Timothy 2:5 - There is one God
1 Corinthians 8:4 - None other God but one
1 Corinthians 8:6 - There is but one God, the Father
James 2:19 - There is one God
Galatians 3:20 - God is one
Matthew 19:17 - None good but one, that is, God
Mark 10:18 - None good but one, that is, God
Mark 12:29 - The Lord our God is one Lord
Deuteronomy 6:4 - The Lord our God is one Lord
2. The Only God. The Bible teaches God\rquote s simple unity not only by stating that He is one, but also by affirming that He is the only God. The word "only" means alone, by one's self, apart, to be solitary.
John 17:3 - Thee the only true God
1 Timothy 1:17 - The only wise God
1 Timothy 6:15 - The blessed and only Potentate
Jude 4 - Denying the only Lord God
Jude 25 - To the only wise God
2 Kings 19:15 - Thou alone
2 Kings 19:19 - Thou only
Nehemiah 9:6 - Thou art Lord alone
Psalm 83:18 - Whose name alone is Jehovah
Psalm 86:9, 10 - Thou art God alone
Isaiah 44:24 - Stretcheth forth the heavens alone
3. There Is None Other. All others are excluded. There is none else. God is alone; beside him none other exists.
Mark 12:32 - There is none other but he
1 Corinthians 8:4 - There is none other God but one
Deuteronomy 4:35 - There is none else beside him
Deuteronomy 4:39 - There is none else
Deuteronomy 32:39 - There is no god with me
1 Samuel 2:2 - There is none beside me
1 Kings 8:60 - There is none else
Isaiah 43:10 - Before me no God, neither after
Isaiah 43:11 - Beside me there is no saviour
Isaiah 44:6 - Beside me there is no God
Isaiah 44:8 - I know not any
Isaiah 45:5 - There is no God beside me
Isaiah 45:6 - There is none beside me
Isaiah 45:14 - There is none else
Isaiah 45:18 - There is none else
Isaiah 45:21 - There is no God beside me
Isaiah 45:22 - I am God, there is none else
Isaiah 46:9 - I am God, there is none else
Jeremiah 10:10 - The Lord is the true God
Joel 2:27 - None else
II. Indications of God's Oneness
1. God's Infinite Attributes. The oneness of God is required by the fact that God is infinite. Reality permits the existence of only one person who is absolutely perfect. There can be only one person who is supreme. Pre-eminence excludes all but one. When one speaks of the original, the source, the first cause, the greatest, the highest, the supreme, the ultimate, the final, he refers to a position that only one person can occupy. God's infinite superiority requires Him to be a single unit, a sole individual, a unique being.
For more than one infinite God to exist would be a contradiction of thought. If several persons existed as God, they would limit each other. They would need to be finite. None would be all in all - the one supreme God.
The idea of God is appropriated to an individual, and does not admit of application to more than one. There cannot be any thing above God, or equal to Him, or which is not dependent upon Him. He is not only the first and the best, but the greatest of beings; and, consequently, He stands alone in the universe. What do we mean by the term God but a being who is infinitely and absolutely perfect? The idea of two equal gods is therefore a chimera. There may be more kings than one, because royalty only implies that each is vested with sovereign authority in his own dominions; but there cannot be a plurality of gods, because, from the nature of things, only one can be possessed of all possible perfections. (Wakefield, Samuel. Christian Theology. New York: Nelson & Phillips, 1873, pp. 140, 141.)
2. The Unity of Nature. The unity of nature reveals the unity of God. All created things form not a multiverse but a universe. The universe evidences itself as the work of one mind, one power, one will - one God. Each new scientific discovery emphasizes the truth of the unity of nature and the oneness of God.
3. Man's Psychological Nature. Man finds a oneness of life in the oneness of God. Unity of personality and purpose is discovered in loyalty to one God. "Hear, O Israel: The Lord our God is one Lord: and thou shalt love the Lord thy God with all thine heart. and with all thy soul, and with all thy might" (Deut. 6:4, 5). Because God is supreme, men are to worship Him supremely. Because God is one, men are to love him with oneness of person. The one God who is all in all insists on total loyalty in His creatures.
Psychology recognizes the need for an organizing principle in man's life. Every circle needs a center. Every solar system needs a sun. Every life needs a supreme loyalty to give it unity and purpose. The oneness of God fills this basic psychological need within man. In supreme loyalty to the one God, man finds a center for his circle and an adequate purpose for his life.
Sinful men cannot worship, obey, and love God in an acceptable way until they become properly related to God through the mediatorial work of Jesus Christ. The sinner must turn his back to sin in repentance before he can turn his face toward God in worship. He must exercise trust in Christ as Sacrifice before he can yield proper obedience to him as Lord. He must surrender to God's saving grace and transforming power before he can be filled with Christ's imparted righteousness which is love. Only through the redemption that is in Christ Jesus, therefore, can man properly fulfill his threefold responsibility of worship, obedience, and love.
(Adapted from Systematic Theology, by Alva Huffer, published by Church of God General Conference, Oregon, Illinois 61061, U.S.A.)