If Jesus was more than just a man, if the authors of the OT and NT believed he was more than a man, not just an angel, but he is incarnate deity, he was both God and man, creature and creator, finite and infinite, omnipotent and impotent, immortal and mortal, how would they express that idea?

They would have to use the names for God, like God and Lord. He'd have to be called God. He'd have to have the attributes of God, be worshipped as God, be prayed to as God. His works would be the works of God, his words would have to be the words of God.

He would be expressed as having two natures, both divine and human. Rom 1:1-5 -- "according to the flesh he is the son of David, but according to the Spirit, he is the Son of God."

Physically, he is the Messiah, but also God.

How would the multi-personal aspect be expressed? Plural pronouns, verbs, adverbs, adjectives.

If Unitarians wrote the Bible they would never communicate these qualities. They would never use plurals for God. They would never attribute the works of God to a creature. They would never give honour or praise to a creature like they give to God.

How would we expect the Bible to be written by:
Point of Comparison Trinitarians Unitarians
Plural Titles In OT: El/Elohim, Adonai, Creators. One/Many Would never use plural titles
Plural words We, Us, plural verbs, nouns, pronouns, adverbs and adjectives. Hebrew: echad/yachid contrast. echad is used of a composite unity; yachid is an absolute singularity.
Maimonides (1138-1204 AD) changed the Shema Israel (Deut 6:4) from echad to yachid in the Middle Ages.
Would never speak in plural pronouns
Works attributed to both the Father and the Son Would never attribute works to both, only to one
Ontology speak about both natures, human and divine Would not speak about 2 natures, only one
Soteriology all 3 are involved in salvation Only the Father would be spoken about as saving anyone
Creation all 3 are involved in creation Only the Father would be spoken about as creating the world
Appearances God appeared in human form on earth. God is and always has been invisible.
Worship Would ascribe bowing, serving, glorifying, honoring, reverence and fear of God, praising, blessing, praying to and obeying the Father and the Son. Would never ascribe the same honour, praise, and thanks to anyone other than the Father.

God is in the plural "Elohim" and the singular "El." "Adonai" is technically plural. "Maker" is plural in Ecc 12:1.

If the authors of the OT believed that the God was multi-personal, would they refer to Him as the Father, Son and Holy Spirit? Prov :what is his name and the name of his Son?

Jewish Writings

Targums: Hebrew scripture translated into Aramaic

Midrash: Commentary of the Hebrew Bible, primarily the Torah "The name of the Messiah is Yaweh", Father, Son and Holy Spirit

Mishnah: A commentary of the Midrash (commentary of the Torah)

Talmuds: Jerusalem and Babylonian Talmud. The written record of the teachings of the Pharisees.

Dead Sea Scrolls.

German Liberal theologians developed a theory that Christianity was not invented by Jesus, instead they are the Greco-Roman mystery religions which deified figures like Caesar and used the word Kurios or Lord in reference to these Demigods. These liberal theologians repeatedly asserted that because the NT refers to Jesus as Kurios this is proof that Jesus is a god, not the God. And that the Jews did not use Kurios in reference to their God.

Do we have any Jewish literature before, during and after Jesus? Yes, we have the Dead Sea Scrolls, Talmuds, Josephus, Philo. These are authentic, unimpeachable Jewish sources. Did Josephus ever use the word Kurios? Yes! Did he ever use it in a Hebrew text to Greek in which he took the name Yahweh and translate it as Kurios? Yes! Philo did the same. These are Jews who are translating a Hebrew text or writing about the Hebrew God and using the Greek term Kurios!

What about the Greek Dead Sea Scrolls. Kurios was used of the God of Israel.

All the Liberals are wrong. Kurios was the word used for the God of Israel by Jews and they did not believe that that word simply meant a Demigod in the sense of Caesar, etc.

Then, you find that in the literature the deity of the Messiah and his pre-existence is clearly taught (in the Pseudepigrapha, the Apocrypha, the Apocolyptic, the Talmuds, the Dead Sea Scrolls).

In the NT, does it say that the Father is God? Why? Arians don't try to speak about this because the arguments they need to prove that the Father is the true God and not "a god" are the same arguments needed to prove that the Son and the Holy Spirit are God are deity as well. (NT References to the Father using Lord God: Luke 1:32,68; Acts 3:22; Rev 1:8; 4:8; 11:17; 15:3; 16:7; 18:8; 21:22; 22:5)