The following is a comment I made in a discussion I had in a Facebook group regarding the distinct person of the Word of the LORD/YHVH/Yahweh/Yehovah/Jehovah in the Old Testament as well as His visible form. Unitarians sometimes deny the personal preexistence of Jesus in the Old Testament. Trinitarians generally believe that the Word of the LORD/YHVH in the Old Testament along with the specific Angel of the LORD/YHVH is the preexistent Jesus (i.e. a Christophany of Jesus). Some Unitarians will deny that the Word of YHVH was a person and that He had a visible form. They claim it was just an audible voice. The following is an exegesis of Samuel chapter 3 that supports the Trinitarian view.
[In the course of the discussion, I wrote:]
That doesn't do justice to what the OT says regarding the Word of YHVH. Because he could be seen at times (e.g. as He did to Abram [in a vision] Gen. 15:1).
In Samuel 3 it says that "And the word of the LORD was rare in those days; there was no frequent V̲I̲S̲I̲O̲N̲" (v. 1).
After Samuel is called by YHVH twice and twice Samuel goes to Eli thinking Eli called him, verse 7 says, "Now Samuel did not yet know the LORD, and t̲h̲e̲ ̲W̲o̲r̲d̲ ̲o̲f̲ ̲t̲h̲e̲ ̲L̲O̲R̲D̲ had not yet been *̲*̲*̲R̲E̲V̲E̲A̲L̲E̲D̲*̲*̲*̲ to him." Implying a visible form. Notice that the Word of the LORD is also simply identified as YHVH in the passage too.
Then in verse 10 it says, "And the LORD C̲A̲M̲E̲ ̲A̲N̲D̲ ̲S̲T̲O̲O̲D̲, calling as at other times,". Notice that it wasn't just an audible voice, but a visible form STOOD before Samuel.
Then in verse 15b it says, "...And Samuel was afraid to tell the V̲I̲S̲I̲O̲N̲ to Eli." Again, not merely an audible voice.
Finally, in verse 21 it says, "And the LORD A̲P̲P̲E̲A̲R̲E̲D̲ again at Shiloh, for the LORD R̲E̲V̲E̲A̲L̲E̲D̲ himself to Samuel at Shiloh by the word of the LORD."
Similarly in Jeremiah chapter 1 the Word of YHVH is sometimes referred simply as YHVH and is apparently in a visible form. Jeremiah says the Word of YHVH came and spoke. In fact, in verse 9 it says of YHVH (evidently the same person as the Word of YHVH) "Then the LORD P̲U̲T̲ ̲O̲U̲T̲ ̲H̲I̲S̲ ̲H̲A̲N̲D̲ ̲A̲N̲D̲ ̲T̲O̲U̲C̲H̲E̲D̲ my mouth." Indicating it wasn't merely an audible voice but a visible form that had a hand that could touch Jeremiah.
These are just some places in the OT that I could cite to document this phenomena. Another would be the encounter of Moses at the burning bush. And others.
