For there is one God and one Mediator between God and men, the Man Christ Jesus,
If we say there are three deities, then we do not have a trinity.
The New Testament makes it clear of the unity of all three being one. Jesus says, I and my father are one. If you've seen me, you have seen the Father. Nowhere does Jesus ever say that His Father and himself are different Gods.
Only God can forgive sins. The pharisees were calling Jesus a blasphemer because he claimed to be God...NOT a God.
All three Persons work together. They are working as one God, and only one God.
Not a great choice is the word persons, as it gives the idea of three separate and distinct "beings." It is what gets people in trouble when talking about The Trinity. You cannot say they are three separate and distinct deities....because then you have no trinity. People who do not believe in the Trinity will use these words against, and perhaps convince you that there is no triune.
Adventists and some of their churches are trying to void the 2nd belief.
Will you stand?
There are numerous problems with polytheism. Not the least of which is a belief in multiple gods. Worse, multiple "gods" that are equal. The whole Gospel of Jesus falls apart. It might not seem like it on the surface, but if Jesus is not God....then what? And there lies the problem.
Are we worshiping another god? Are we following another god? What happened to God of the Old Testament? If Jesus is not God, then we would have nothing more than another made up religion following another deity. Another buddha? Another cult or sect? Is Christianity based on the true God, or more Gods? Why stop at just three? Jesus never told anyone that he was starting a new religion. He came to complete and promote the old one.
If God never changes, and is forever, then how can we possibly say Jesus is another God? What happened to the first one?