Because God wills to manifest Himself in 3 ways, or 10, or 1000, or ONE, doesn’t make Him that many persons. “Hear, O Israel, the Lord your God is ONE Lord.”
He can also manifest Himself in many presentations simultaneously, but He remains One Lord. Who spoke to and by Isaiah declaring there was only One Lord and One Savior, and no other?
Isaiah 43:11 (KJV)
I, even I, AM the Lord ; and beside Me there is no Saviour.
Isaiah 59:16 (MKJV)
And He saw that there was no man, and wondered that there was no intercessor. Therefore His own arm brought salvation to Him; and His righteousness sustained Him.
Was it the Father speaking to him or the Son? Which?
I’ll tell you something else. If I pray to God, and HE answers me, who is it that answers? They or He? When in the early seventies, I cried out to the Only Name under Heaven whereby I could be and was saved, Jesus Christ, who answered me? Jesus Christ did.
And with Thomas, I cried out, “My Lord and my God,” and He not only did not correct or rebuke me, but He also SAVED ME. Jesus Christ, the One Who spoke to Isaiah saved me, He and He Alone, the One God of Israel and of the universe.
We believe, according to the Scriptures, that Melchizedek was a man, not the Lord Jesus Christ or the Angel of the Lord. Introducing Melchizedek, the Scriptures say: “And Melchizedek the king of Salem brought forth bread and wine. And he was the priest of the most high God” (Genesis 14:18 MKJV).
Yes, it is "Who" is the Christ, and the answer is, of course, “the Lord Jesus.” However, we can also ask "What" is the Christ? The answer is exciting.
If Jesus Christ isn’t God, then why is He worshipped as God in the Scriptures? A man condemns us as false teachers for declaring Christ is God, but we prove his arguments have no foundation in the truth because he lacks the knowledge of God. Indeed, the very thing he needs is to worship Jesus Christ as God in order to receive forgiveness of sins, healing, understanding, and peace with God, as the Lord Jesus has graciously done for us.