In supplementation to having already abundantly shown (in a work on mine own) that Jesus is God by nature - to whom are ascribed many uniquely divine attributes, titles and glory, and "from everlasting," I want provide more on the Trinity, from my own study, and again, based upon Scriptural substantiation, logic and reasoning, which itself is Scriptural.
And God said, Let US make man in our image, after OUR likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth. So God created man in his own image, in the image of God created he him; male and female created he them. (Genesis 1:26,27)
And the Lord God said, Behold, the man is become as one of US , to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever: (Genesis 3:22)
And the Lord said, Behold, the people is one, and they have all one language; and this they begin to do: and now nothing will be restrained from them, which they have imagined to do. Go to, let US go down, and there confound their language, that they may not understand one another’s speech. (Genesis 11:6-7)
Also I heard the voice of the Lord, saying, Whom shall I send, and who will go for US ? Then said I, Here am I; send me. (Isaiah 6:8)
Here we have God referring to Himself in the plural, as creator, and while the trinitarian denialist may argue that this refers to angels, yet in NO PLACE is any creative activity ascribed to them or to any created being, not to anyone else but God.
Thus saith the Lord, thy redeemer, and he that formed thee from the womb, I am the Lord that maketh all things; that stretcheth forth the heavens alone; that spreadeth abroad the earth by myself; (Isaiah 44:24)
Yet we are plainly told that,
In the beginning was the Word, and the Word was with God, and the Word was God. The same was in the beginning with God. All things were made by him; and without him was not any thing made that was made. (John 1:1-3)
For by him were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him: (Colossians 1:16)
Hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds; Who being the brightness of his glory, and the express image of his person, and upholding all things by the word of his power, when he had by himself purged our sins, sat down on the right hand of the Majesty on high; (Hebrews 1:2-3)
Moreover, concerning "Whom shall I send, and who will go for US ?," (Isaiah 6:8) in context this refers to Isaiah seeing "the Lord sitting upon a throne, high and lifted up, and his train filled the temple Above it stood the seraphims: each one had six wings; with twain he covered his face, and with twain he covered his feet, and with twain he did fly. And one cried unto another, and said, Holy, holy, holy, is the LORD [yehôvâh] of hosts: the whole earth is full of his glory. Then said I, Woe is me! for I am undone; because I am a man of unclean lips, and I dwell in the midst of a people of unclean lips: for mine eyes have seen the King, the LORD of hosts." (Isaiah 6:1-5)
In this context the Lord asks "Whom shall I send, and who will go for US" to which Isaiah answers, "Here am I; send me," (v. 8) and who is charged to tell the people of the judgment of God, that, "Hear ye indeed, but understand not; and see ye indeed, but perceive not. Make the heart of this people fat, and make their ears heavy, and shut their eyes; lest they see with their eyes, and hear with their ears, and understand with their heart, and convert, and be healed." (Isaiah 6:9-10)
from here we will fast forward to John 12:34b and following in which we a very fundamental question is asked, "who is this Son of man?" To which Jesus responds with the principle that one must obey the light one has to receive more light, vs. darkness:)
Then Jesus said unto them, Yet a little while is the light with you. Walk while ye have the light, lest darkness come upon you: for he that walketh in darkness knoweth not whither he goeth. 36 While ye have light, believe in the light, that ye may be the children of light. These things spake Jesus, and departed, and did hide himself from them. For indeed, in judgment, "Verily thou art a God that hidest thyself, O God of Israel, the Saviour." (Isaiah 45:15) With the reason being that,
But though he had done so many miracles before them, yet they believed not on him: That the saying of Esaias the prophet might be fulfilled, which he spake, Lord, who hath believed our report? and to whom hath the arm of the Lord been revealed? Therefore they could not believe, because that Esaias said again, He hath blinded their eyes, and hardened their heart; that they should not see with their eyes, nor understand with their heart, and be converted, and I should heal them. These things said Esaias, when he saw his glory, and spake of him. (John 12:37-41)
It is the last verse that is particularly relevant to the subject of the Trinity, for it tells us that the Lord that Isaiah/Esaias saw when he was given this prophecy of judgment was the Lord Jesus, for "These things said Esaias, when he saw his glory, and spake of him, thus answering the question, "who is this Son of man?" Which Jesus, being the brightness of God s glory, and the express image of His person proceeds to a affirm, declaring, "He that believeth on me, believeth not on me, but on him that sent me. And he that seeth me seeth him that sent me." (John 12:44-45)
How does this work to establish the Trinity? By first disallowing God from being an absolute unity, since Scripture, which cannot be broken or contradict itself, cannot declare that God created the universe" by Myself" and that all things were made by the Word/the Son; "and without him was not any thing made that was made" (John 1:1-3) unless "by Myself" at least means the Father with and thru Son.
But what of the Spirit? For this we have the statement of Job that,
The Spirit [rûach] of God hath made me, and the breath [neshâmâh] of the Almighty hath given me life. (Job 33:4)
While it is true that the word for "Spirit" (rûach) also can be translated means "breath" or "wind," which it is in a minority of time, and the word for breath here (neshâmâh) also can be translated Spirit, and thus it depends upon the context. And it was the rûach of God that made Job and over 200 times rûach contextually refers to the searching, convicting, empowering, revelatory Spirit of God (like as "And the LORD said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years." - Gen 6:3; "And the Spirit of the LORD will come upon thee, and thou shalt prophesy with them, and shalt be turned into another man" - 1Sa 10:6) or the spirit of man (I call to remembrance my song in the night: I commune with mine own heart: and my spirit made diligent search - Psa 77:6).
And when "neshâmâh" is used in such contexts as Proverbs 20:27 "The spirit of man is the candle of the Lord, searching all the inward parts of the belly" then it is obviously not referring to breath, but as with 1 Corinthians 2:11, "For what man knoweth the things of a man, save the spirit of man which is in him? even so the things of God knoweth no man, but the Spirit of God," it is referring to part of the triune nature of man, as in "And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ." (1 Thessalonians 5:23)
Yet while it was the rûach of God that made Job, the argument is made that the spirit lacks personhood, thus reducing the Spirit to simply be an active instrumental force, or energy, yet like as Christ is revealed as actually being incarnated, with feelings, versus being an entity whose appearance did not conform to what He materially was, so also the revelation of the Spirit shows that He possesses attributes of personality.
First, not only are we told that "the LORD said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years" (Gen 6:3) but that the Spirit who searcheth all things, (1 Corinthians 2:10) can be grieved, thus having emotions.
And grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption. (Ephesians 4:30)
Likewise, He can be lied to, as God:
But Peter said, Ananias, why hath Satan filled thine heart to lie to the Holy Ghost, and to keep back part of the price of the land? Whiles it remained, was it not thine own? and after it was sold, was it not in thine own power? why hast thou conceived this thing in thine heart? thou hast not lied unto men, but unto God. (Acts 5:3-4)
Next, not only is the Spirit called "He," but that He gives gifts according to His will But all these worketh that one and the selfsame Spirit, dividing to every man severally as he will [willing, disposed]. (1 Corinthians 12:11)
Moreover, speaks and intercedes for those born of Him, indicative of will:
Likewise the Spirit also helpeth our infirmities: for we know not what we should pray for as we ought: but the Spirit itself maketh intercession for us with groanings which cannot be uttered. (Romans 8:26)
And the Spirit, together with the Father and the Son, are together those in whose are together in the baptism of Jesus,
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: And lo a voice from heaven, saying, This is my beloved Son, in whom I am well pleased. (Matthew 3:16-17)
Note however, that as in the marital union of biological men and women, though both are human by nature, yet on earth there are positional and functional distinctions between them, so also as regards the Father, Son and Spirit, while sharing the same nature, yet their are positional and functional distinctions, as the Father is the head of Christ,(1 Corinthians 11:3; and who in turn sends the Spirit with and from the Father, (John 15:26) and tells the Spirit what to say from Him. John 16:13-15)
And while Christ is now functioning as Lord of the universe as a result of humbling Himself in obedience, even the death of the cross, yet after He puts all His enemies under His feet, (Acts 2:33-36) and to whom every knee shall bow, (Philippians 2:8-11) then He will deliver all back to the Father so that He, as God, will rule over all. (1 Corinthians 15:24-28) To the glory of God.
Finally, while there is more, the Spirit, as one of the "Us," and Our" of Genesis and Isaiah, are together as the name one is baptized into,
Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: (Matthew 28:19)
And together as those whom those born of the Spirit are blessed by, as persons bestowing things:
The grace of the Lord Jesus Christ, and the love of God, and the communion of the Holy Ghost, be with you all. Amen.
Thus not only is God as an absolute unity contradicted by Scripture clearly revealing to the deity of Christ, but also the Spirit of Christ is not only show to be Divine, but testifying to His personhood.
But only those of penitent, heart-purifying, regenerating effectual faith, (Acts 10:43-47; 15:7-9) which is imputed for righteousness, (Romans 4:5) and is shown in baptism and following the Lord, (Acts 2:38-47; Jn. 10:27,28) who was sent by the Father to be the savior of the world. (1 John 4:14) can or will know of this grace of the Lord Jesus Christ, and the love of God, and the communion of the Holy Ghost to any actual real degree.
And by which faith the redeemed soul is "accepted in the Beloved" and
positionally seated with Him in Heaven, on His account, glory to God.
(Ephesians 1:6; 2:6; cf. Phil. 3:21) And those who die in that obedient
faith will go to be forever with Him at death or His return (Phil 1:23;
2Cor. 5:8 [“we”]; Heb, 12:22,23; 1Cor. 15:51ff'; 1Thess. 4:17) In
contrast to those who were never born of the Spirit or who terminally
fall away. (Gal. 5:1-4; Heb. 3:12; 10:25-39)