False Teaching about the Trinity

"...try to deny the doctrine of the Trinity and you'll loose your salvation, try to understand it and you'll loose your mind."  ~ Stanley Grenz

"The doctrine of the Trinity is truth for the heart. The fact that it cannot be satisfactorily explained instead of being against it, is actually in its favor; such a truth had to be revealed, no one could have imagined it." ~ A.W. Tozer

Tri-Theism:
Modern Example: Mormonism - Jesus was a created being and the Spirit-brother of Lucifer, who became a god. Mormonism teaches that there are many gods and we too can become gods.

Modalism (also Sabellianism, Modalistic Monarchianism):
Modern Example: United Pentecostal Church - "Jesus only", there is only one God who manifests himself in three modes. God is essentially playing different roles and the assumption is that in the Old Testament he revealed himself as the Father, in the New Testament God reveals himself as Jesus, and in the church-age as Holy Spirit.

Arianism (Dynamic Monarchianism):
Modern Example: Jehovah's Witnesses - Denying the deity of Jesus and the Holy Spirit. Jesus was a created being adopted by God, and the Holy Spirit is simply the power of God or a force..."  full text:  http://www.thecityaustin.com/sermon/the-trinity/