The Eternal God: Against the Evolutionary God of Mormonism

"Of old You laid the foundation of the earth,
     and the heavens are the work of Your hands.
They will perish, but You will remain;
     they will all wear out like a garment.
You will change them like a robe, and they will pass away,
     but You are the same, and Your years have no end."
- Psalm 102:25-27 

One of the lesser-known doctrines of Mormonism is that God is only God here, not throughout the universe. Rather, he was once a man on another planet who was exalted to godhood by the God of that planet. In the same way, they believe that good Mormons will be exalted to godhood and receive their own planets. 

This is one of the most-explicitly antibiblical doctrines of Mormonism. The Bible explicitly tells us that the deity of God, the true, living biblical God, has always existed, and has always been God. Where the Mormon universe is eternal and self-existing (attributes of deity), the Christian, triune, biblical God is eternal and self-existing, and the universe has only a derivative existence: "In Him we live and move and have our being" (Acts 17:28).

This alone should be sufficient evidence to demonstrate that the Mormon claim to the Christian name is a deception.