Isaiah 43:10-13 “You are My witnesses,” declares the Lord, “and My servant whom I have chosen, so that you may know and believe Me and understand that I am He. Before Me there was no God formed, and there will be none after Me. 11 “I, even I, am the Lord, and there is no savior besides Me. 12 “It is I who have declared and saved and proclaimed, and there was no strange god among you; so you are My witnesses,” declares the Lord, “and I am God. 13 “Even from eternity I am He, and there is none who can deliver out of My hand; I act and who can reverse it?”
Isaiah 45:21 “Was it not I, the Lord?And there is no God apart from me, a righteous God and a Savior; there is none but me.”
Deuteronomy 6:4 “Hear, O Israel! The Lord is our God, the Lord is one!”
The first essential doctrine of the Christian faith is there is only one God.All groups claiming to be Christian, which believe in more than one God, are false belief systems according to the Bible.A Christian must believe there is only one true God by nature.A definition of nature is the essential attributes or characteristics of a living being or thing.Examples can include a human nature or divine nature.
Mormonism teaches the Father is God, the Son is a second God, and the Holy Spirit is a third God.Mormonism is therefore polytheistic and is not Christian.They also believe all three gods came into existence at some point in time.However, in Isaiah 43:13 (and many other places) we see God in existence from all eternity.The Bible says God has no beginning or end again showing Mormonism is not Christian. Psalms 90:2 “Before the mountains were born or You gave birth to the earth and the world, even from everlasting to everlasting, You are God.”
Jehovah Witnesses also believe in more than one god.The Watchtower Organization teaches Jesus was the first creation of Jehovah God.Therefore, Jesus was a god, a mighty god, a lesser god, a created being.However, Isaiah 43:10 says, “…Before Me there was no God formed, and there will be none after Me.”Isaiah clearly says no God formed before Him and none after; Jesus cannot be a created god because there are none.Jehovah Witnesses are not Christians; they believe in more than one god.
All references to other “gods” in the scripture refer to false gods.Satan in 2 Corinthians 4:4 is called the god of this world. Satan is a false god.When men are called gods, they still have a nature human.Psalms 82:6-7 I said, “You are gods, And all of you are sons of the Most High. 7 “Nevertheless you will die like men And fall like any one of the princes.”Here God calls the wicked judges and rulers gods; they were supposed to be His representatives but were still by nature men.And how do we know that?Verse 7 says they will die like men; God cannot die.These wicked rulers were definitely false gods with a human nature and not a divine one.Galatians 4:8 Paul writes, “However at that time, when you did not know God, you were slaves to those which by nature are no gods.”
There is by nature only one true God.This one true God is triune; one God subsisting in 3 persons; Father, Son, and Holy Spirit; co-equal and co-eternal.Belief in one God is an essential doctrine of Christianity.