I have heard arguments about this since I became a Christian 25 years ago. There are some Christians who say that in order to be a "true" Christian, that person must believe in the Trinity.
The Trinity isn't actually taught in the Bible. Jesus Himself never spoke of it, Paul never spoke of it. I studied a bit about how they came up with the Trinity- different verses they strung together to prove it exists.
The fact has been for the past few years I have had a lot of questions about it. I accepted it without question for the first 20 years of my faith and then after a debate on a Christian site I used to post at (but haven't lately) I began to question it.
I am not saying I don't believe in it, I am just questioning it.
I am asking the other Christians on this board if questioning or not believing in the Trinity can stop one from being a Christian in your eyes.
Jesus says, being, saved,or born again is synonymos with wind John 3:The wind blows where it wishes, and you hear the sound of it, but cannot tell where it comes from and where it goes. So is everyone who is born of the Spirit."
Salvation is a gift from God, by believing in his son as the atoning sacrifice, but it is an act brought about by the Holy Spirit
As you said,the word trinity is not in scripture and in and of itself is not , nor has it ever been a means to salvation.
The bible says Rom 1:16 "the gospel is the power of God unto salvation for everyone who believes"...for in it the righteousness of God is revealed....
Jhn 1:14-13But as many as received him, to them gave he power to become the sons of God, [even] to them that believe on his name:Which were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God.
2Cr 7:10 For godly sorrow produces repentance leading to salvation, not to be regretted; but the sorrow of the world produces death.
As you said, there are several pieces of text that refer to the mentioning and the distinguishing of the Holy Spirit. As a matter of fact, the whole of scripture identifies God the father, Jesus Christ the Son and the power and person of the Holy Spirit. They all work together in the process of salvation.
I guess what I'm saying is that to be born again or saved is not through knowledge of the Godhead or trinity, it is recognising personal sin and immediately seeing your need for a savior, it is an inner witness of conviction brought about by the Holy Spirit that leads us to call on Christ and this is all gifts from God the Father.