Taken from the only time this quote was not included in a compilation:
“The world was made by him, “and without him was not anything made that was made.” If Christ made all things, he existed before all things. The words spoken in regard to this are so decisive that no one need be left in doubt. Christ was God essentially, and in the highest sense. He was with God from all eternity, God over all, blessed forevermore.” RH April 5, 1906, par. 6
Ephesians 3:9 and Hebrews 1:1-2 speak clearly that God the Father created all things through His Son. John 1:1–3 says that all things were created by Christ, without Him nothing was made.
Therefore, over all creation, Christ was God in essence, or essentially. As ruler of all because of creation, He was in the highest sense the God of those things He had created. Never does the Bible say that Jesus Christ is, or was, God of His Father. We do see though, that the Father is God of His Son. Hebrews 1:8-9, Revelation 3:12, etc.
Just as my son is human essentially, and in the highest sense (because he is my son), the son of God is ‘divine’ essentially, and in the highest sense (because He is the son of God).
Before things were created that we know about as humans that determine time (the world rotating around the sun, the world spinning on its axis, or the moon going around our world), we do not know of anything that determined time in that sense. That is what Ellen White seems to have called “all eternity.“ From that era, Christ, the only begotten Son, was with God. He was God over all things He created—not over His Father.
You’ll notice that this quote was published in 1906, which was one year after Ellen White had written a response to a book entitled “Living Temple” by Dr. John H. Kellogg. White’s response book was entitled, “Ministry of Healing.” At that time she was combating the spiritualistic ideologies that Kellogg was bringing into the church, and she was not intending to sound trinitarian.
The reason this short commentary starts out with the idea of compilations is because, during the time most EGW compilations have been put together, many of the publishing leaders that helped put those compilations together were trinitarian in thinking. This is not the same way of thinking Ellen White had while she was living and writing.