There is no doubt that God the Father is God. But if the Son of God, Jesus, is also God, and the Holy Spirit is also God, how do you reconcile that with the Father's own statement that He alone is the one true God and that there is no other besides Him?
God the Father said, for God the Father alone is the one and only Savior.
ISAIAH 43:10-11
10 Ye are my witnesses, saith the Lord, and my servant whom I have chosen: that ye may know and believe me, and understand that I am he: before me there was no God formed, neither shall there be after me.
11 I, even I, am the Lord; and beside me there is no saviour.
How would you refute this?
I will try again, using different words. Those of us who believe in the Trinity, one God in three "Persons", do
NOT believe in three Gods. There is, as the Bible assures us, one God.
You quote Isaiah 40:10-11, and say that it is about God the Father. However, the verses mention "God" and "Lord, but not "Father."
You say that Jesus Christ is not God. That goes against what John writes in John 1:1: "And the Word was God." In case there is any uncertainty about Who the Word is, John says in John 1:14:
(Joh 1:14 NKJV) And the Word became flesh and dwelt among us, and we beheld His glory, the glory as of the only begotten of the Father, full of grace and truth.
Thomas, when he saw the risen Jesus Christ, said to Him, "My Lord and my God!" If Jesus Christ were not God, why did Jesus not rebuke Thomas? But there were no words of rebuke:
(Joh 20:26-29 NKJV) And after eight days His disciples were again inside, and Thomas with them. Jesus came, the doors being shut, and stood in the midst, and said, "Peace to you!" Then He said to Thomas, "Reach your finger here, and look at My hands; and reach your hand here, and put it into My side. Do not be unbelieving, but believing." And Thomas answered and said to Him, "My Lord and my God!" Jesus said to him, "Thomas, because you have seen Me, you have believed. Blessed are those who have not seen and yet have believed."
Then we have Jesus saying and doing things that only God can do and say. He forgave sins. Yes, mere men can forgive people who sin against them, but Jesus forgave all the sins of the people He forgave.
He walked on water, raised the dead, calmed a storm by telling it to be still, turned many gallons of water into the finest wine, knew what people were thinking, and much more.
Then the Holy Spirit. I quoted verses from Acts 5, where Peter asks Ananias why he has lied to the Holy Spirit. Then he tells him, " You have not lied to men, but to God." If the Holy Spirit is not God, how can lying to the Holy Spirit be lying to God?