The Scriptures do not declare Yeshua (Jesus) to be "God". English translations do that. The Scriptures declare he is either "elohim" or "theos". Both words are used of men as well as the Father. Since there is only one God and a multitude of verses declare that God is Father YHWH, then when "elohim" or "theos" are used of the Son, it must be in a lesser sense than YHWH being "Elohim" or "Theos". Yeshua is an "elohim" in the same sense that the Israelites of Psalm 82:6 are "elohim".
Also, the Holy Spirit is not a third person who is also "God". The Holy Spirit is the mind, influence and power of the only true God.
You cannot grieve the Holy Spirit unless He is a Person.
Ephesians 4:30 And grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption.
He cannot be considered a Witness unless He actually bears testimony of the Son through us.
John 15:26 But when the Comforter is come, whom I will send unto you from the Father, even the Spirit of truth, which proceedeth from the Father,
he shall testify of me: 27 And ye also shall bear witness, because ye have been with me from the beginning.
The only way God as God can bear witness in establishing a testimony and judge any one is by having Three Witnesses within that One God, otherwise as the One Person God, God cannot establish a word in creation nor judge any one in according to His words when mankind is to bear witness and judge by this standard.
Deuteronomy 17:6At the mouth of
two witnesses, or
three witnesses, shall he that is worthy of death be put to death; but at the mouth of one witness he shall not be put to death.
Deuteronomy 19:15One witness shall not rise up against a man for any iniquity, or for any sin, in any sin that he sinneth: at the mouth of
two witnesses, or at the mouth of
three witnesses, shall the matter be established.
Matthew 18:16But if he will not hear thee, then take with thee one or
two more, that in the mouth of
two or
three witnesses every word may be established.
2 Corinthians 13:1This is the third time I am coming to you. In the mouth of
two or
three witnesses shall every word be established.
So when you read this:
John 8:17 It is also written in your law, that the testimony of two men is true.
That is why God the Father spoke from Heaven at His water baptism with the Witness of the Holy Spirit lighting on Jesus also to make the God's witness true.
Matthew 3:15 And Jesus answering said unto him, Suffer it to be so now: for thus it becometh us to fulfil all righteousness. Then he suffered him. 16 And Jesus, when he was baptized, went up straightway out of the water: and, lo, the heavens were opened unto him, and he saw the Spirit of God descending like a dove, and lighting upon him: 17 And lo a voice from heaven, saying, This is my beloved Son, in whom I am well pleased.
This was to fulfill the prophesy in Isaiah where God is speaking and yet it is the Lord God and His Spirit that sent God the Redeemer.
Isaiah 48:16 Come ye near unto me, hear ye this; I have not spoken in secret from the beginning; from the time that it was, there am I: and now the Lord God, and his Spirit, hath sent me. 17 Thus saith the Lord, thy Redeemer, the Holy One of Israel; I am the Lord thy God which teacheth thee to profit, which leadeth thee by the way that thou shouldest go.
So pray about that, brother. The Triune God exists... 1 John 5:7 originally belongs in scripture, otherwise how can the witness of God be greater then men's in 1 John 5:9 by the rest of the scripture if He was only a One Person God?
http://solascriptura-tt.org/Bibliologia-PreservacaoTT/1Jn5-7-Ruckman.htm