One of the clearest texts proving a trinity is John 1:1 “In the beginning was the Word, and the Word was with God, and the Word was God.”
How do you explain this?

Answer:

This text is much misunderstood and has been misused to support a teaching that totally opposes what the text actually says. Let us examine the text briefly in the original Greek:

εν 1722  αρχη 746  ην 2258  ο 3588  λoγoς 3056  και 2532  o 3588  λoγoς 3056
    In        beginning     was        the         Word           and          the         Word

ην 2258    πρoς 4314    ton 3588    Θεoν 2316    και 2532    Θεoς 2316   
  was           with                 the              God               and             God         

ην 2258   o 3588   λoγoς 3056
   was            the         Word

A very casual look at the original text tells us that the two words translated as “God” in that text are not identical. The first one is a noun (Θεoν) referring to  the Father, and the other is an adjective (Θεoς) which refers to Jesus. You can tell the difference between the two by looking at the last letter of the two words.

It is for this reason that many translations render the verse in a way that recognizes this fact. For example, translations by James Moffatt, Hugh J. Schonfield and Edgar Goodspeed render it: "...and the Word was divine."

Other variations also exist. Today's English Version reads: "...and he was
the same as God."
The Revised English Bible reads: "...and what God was, the Word was."
As you can see, different translations give it a meaning in harmony with the original. Thus this text is telling us is that the Word, Christ, is divine just like the Father (possessing the "God-nature"). It does not tell us that Christ is God the Father, one and the same person.

However, the question that we need to address is “what beginning is this text talking about?” Was this the beginning of earth? Was it the beginning of creation? The answer is No. The reason being that creation is not mentioned
in the verse at all. That comes in v.3 “All things were made by him; and without him was not any thing made that was made”

Thus, if all things were made by him (Christ the Word) then the beginning in
v.1 must be before creation. Our parallel text is found in Proverbs 8: 22-30.
This passage is divided in 2 parts. The first part talks about the birth of Christ
in heaven before anything was created. While the second part tells us who
was with God during the creation:

“The LORD possessed me in the beginning of his way, before his works of old.
I was set up from everlasting, from the beginning, or ever the earth was.
When there were no depths, I was brought forth; when there were no
fountains abounding with water. Before the mountains were settled, before t
he hills was I brought forth: While as yet he had not made the earth, nor
the fields, nor the highest part of the dust of the world.” 22-26

Christ was possessed/set up/brought forth in the beginning of God's ways.
Colossians 1:15 puts it this way “Who is the image of the invisible God, the
firstborn of every creature:”

This beginning was “before his works of old”, before “the earth was”, “when
there was no depths”, “when there were no fountains”, “before the mountains
were settled, before the hills”, “While as yet he had not made the earth…etc”
Christ is saying that He was brought forth in the beginning before these creative acts.

The second part of the passage in Proverbs 8 says: “When he prepared the
heavens, I was there: when he set a compass upon the face of the depth: When he established the clouds above: when he strengthened the fountains of the deep: When he gave to the sea his decree, that the waters should not pass his commandment: when he appointed the foundations of the earth: Then I was by him, as one brought up with him: and I was daily his delight, rejoicing always before him;” v.27-30

This section tells us that Christ, the Word, was with God during the creation.
The RSV renders v.30 this way “then I was beside him, like a master workman;
and I was daily his delight, rejoicing before him always,” which brings out the
point that Jesus was a workman in the creation of the world, or as John 1:3 puts it “All things were made by him; and without him was not any thing made that was made”

Colossians 1: 16, 17 says the same thing “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: And he is before all things, and by him all things consist”

Here are the three references side by side:

Thus, John 1: 1-3 not only does not support the trinity, but properly understood, teaches and supports the divine sonship of Christ.

Spirit of Prophecy: In addition to that, here is what E. G. White had to say:

“Christ shows them that, although they might reckon His life to be less than fifty years, yet His divine life could not be reckoned by human computation. The existence of Christ before His incarnation is not measured by figures.” {Signs of the Times, May 3, 1899}

“Angels of God looked with amazement upon Christ, who took upon Himself the form of man and humbly united His divinity with humanity in order that He might minister to fallen man. It is a marvel among the heavenly angels. God has told us that He did do it, and we are to accept the Word of God just as it reads. And although we may try to reason in regard to our Creator, how long He has had existence, where evil first entered into our world, and all these things, we may reason about them until we fall down faint and exhausted with the research when there is yet an infinity beyond.” {7BC 919.5}

“The Lord Jesus Christ, the divine Son of God, existed from eternity, a distinct
person, yet one with the Father. He was the surpassing glory of heaven. He was the Commander of the heavenly intelligences, and the adoring homage of the angels was received by Him as His right. This was no robbery of God. "The Lord possessed me in the beginning of his way," He declares, "before his works of old. I was set up from everlasting, from the beginning, or ever the earth was. When there were no depths, I was brought forth; when there were no fountains abounding with water. Before the mountains were settled, before the hills was I brought forth; while as yet he had not made the earth, nor the fields, nor the highest part of the dust of the world. When he prepared the heavens, I was there: when he set a compass upon the face of the depth."”
{RH, April 5, 1906 par. 7}

“The Sovereign of the universe was not alone in His work of beneficence. He had an associate--a coworker who could appreciate His purposes, and could share His joy in giving happiness to created beings. "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." John 1:1, 2. Christ, the Word, the only begotten of God, was one with the eternal Father-one in nature, in character, in purpose-the only being that could enter into all the counsels and purposes of God.” {PP 34.1}

Here are two statements from E. J. Waggoner and Uriah Smith that confirm to
us what we have seen: "The word was "in the beginning." The mind of man
cannot grasp the ages that are spanned in this phrase. It is not given to men to know when or how the Son was begotten” E. J. Waggoner, Christ and His
Righteousness, p.9

"God alone is without beginning, at the earliest epoch when a beginning could
be, a period so remote that to finite minds it is essentially eternity, appeared the Word "In the beginning was the Word, and the Word was with God, and the Word was God." John 1:1" Uriah Smith, Looking Unto Jesus 1898, p. 10