Jesus is "the Word of God" and the "the Son of God." That little word "of" has an important meaning. It establishes a relationship between two separate entities. A son is not his own father, nor can a father be his own son. If God has a son, therefore, that son cannot be God Himself.
But the Son can, and does, speak for God--hence the "Word" title. According to the Scriptures, Jesus, as the Word, has spoken everything into existence, being the spokesperson for God.
1In the beginning was the Word, and the Word was with God,
and the Word was God. 2The same was in the beginning with
God. 3All things were made by him; and without him was not
any thing made that was made. (John 1:1-3, KJV)
Believest thou not that I am in the Father, and the Father in me? the
words that I speak unto you I speak not of myself: but the Father that
dwelleth in me, he doeth the works. (John 14:10, KJV)
Clearly, the Father is in Jesus, dwelling in him. This does not say that the Father is Jesus--no; they are two separate entities. However, this does tell us something important: Jesus speaks the Father's words.
So if Jesus speaks the Father's words, then if he were to say "I AM God"--those words would be God's words, because the Father is God. As Jesus says plainly, he is not speaking his own words.
For I have not spoken of myself; but the Father which sent me, he gave
me a commandment, what I should say, and what I should speak. (John
Again, we see clearly that 1) Jesus is not speaking his own words, but those of the Father who sent him; and 2) These are two separate entities.
The Father is not sending himself. Nor is the Father commanding himself to speak certain words. That would be irrational. And we know who the Father is, for Jesus prayed to the Father in John 17 and called Him "the only true God" (verse 3). It follows, then, that Jesus, who is separate from the Father, cannot be "the only true God." In fact, he cannot be God at all--but God dwells in him. (See also 2 Corinthians 5:19.)
The same John who wrote the book of John and said all things were made by "the word," writes in the book of Revelation:
And unto the angel of the church of the Laodiceans write; These things
saith the Amen, the faithful and true witness, the beginning of the
creation of God; (Revelation 3:14, KJV)
That word "beginning" is from the Greek "ἀρχὴ", which means just that: beginning. Every time this word appears in the Greek, the KJV translates it as "beginning." To render this word as "originator" is borderline irresponsible: if one wishes to use this root, why not "origin" in place of "originator"? Whereas "beginning" can fill both senses of meaning, this cannot be done with the "origin" root. Translators have done the readers interpretation for them. And does it fit?
The beginning ("ἀρχὴ") of the gospel of Jesus Christ, the Son of God;
(Mark 1:1, KJV)
This is the exact same Greek word. Should it read "The originator of the gospel of Jesus Christ, the Son of God"?
Obviously, that would be inaccurate. Neither is "originator" accurate in Revelation 3:14.
The "God" referenced in Revelation 3:14 is the only true God--the Father. Jesus, God's son, speaks God's word, including the word of creation which has brought all things into existence. God has created everything through Jesus.