Unitarian vs Trinitarian: Does Father equal Holy Spirit? Why is it important to believe that Jesus was actually the Son of God Incarnate? The Old Testament people didn't know that! Why isn't the Holy Spirit the Father since it was He overshadowing Mary instead of the Father? JWs, Mormons & the Trinity: You just explained that Christians believe the Trinity differently, but yet the JWs & Mormons are called a cult because they believe it differently. Why?