Do we need to believe in the Trinity to be saved?

[RileyG]

That is the reason for the Nicene Creed. Each line of the Creed refutes a particular heresy. It begins, "We believe in one God...". That is to counter the ancient gnostic belief in two gods, one who created invisible things such as the spirit, the other a lesser god who created all things material. The Creed continues, "the Father Almighty, Creator of all things visible and invisible...". It then continues, "And in one Lord Jesus Christ...true God of true God...".

Any other profession of faith is not Christian, it is some other thing. Another heresy of some of the ancient Gnostics was that they claimed Jesus for themselves, but taught that he was only a "spirit being" with no physical body. That led to this:

1Jo 4:3 And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world

So to believe in Jesus as your Lord and Savior isn't going to help much if you believe in the wrong Jesus. In the end, that is the reason for the Trinitarian form of baptism. A baptism not using the Trinitarian formula isn't valid. If a person is only baptized "in Jesus name" they don't really know which Jesus they are being baptized for.

Well written and well said.