Q: #101. What is modalism?
A: Modalists reject the trinitarian view that most Christians hold. The Bible teaches that there is one God manifest in three distinct persons, who are co-equal and have existed eternally together. However, the modalist believes in one God manifest in three “modes.”
These modes have followed each other, and have never existed together, therefore, they are not all eternal. It is taught that the Father was God in the Old Testament. The Father existed until Jesus was born, then Jesus became God. After Jesus’ ascension, the Holy Spirit became God.
As I understand it, most modalists seem to believe that it is actually Jesus who has become the Father, Son, and Holy Spirit, although some believe the Father actually took on each of those modes.
Other names for modalism are “oneness” or Sabellianism. The main denomination that holds to this modalist view is the United Pentecostal Church. One distinctive feature about them is that they baptize in Jesus’ name ONLY, and believe one is lost if they aren’t.
Related: Explain the Trinity!