Why Jesus had to be a human
Many Trinitarians have a hangup to Unitarianism due to our offering praise to a (mere) man. They have been told that praise can only be directed to God himself and not to a man He has given authority to. But I find the Bible is clear as to why the Messiah must be a man and cannot be God himself.
Consider John 3:14 - "as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up" (KJV)
Jesus was referring to the Old Testament, when the Israelites were suffering from poisonous snake bites (due to a punishment from disobeying God). God told Moses to fashion a bronze serpent head and put it on the end of a pole. He told him to hold it up and whoever looked upon it would not die but live and be saved. We can see how that directly parallels Christ's Glory on the cross, and that's why he mentioned it.
The takeaway from this is that there isn't any intrinsic divinity within the bronze serpent. It is that God's authority was in it. What God had set forth would be accomplished; His future sinless messianic son would be glorified on the cross and whoever looked to Him, would be saved.
If we read Deut 18:14-20 you will find the prophecy given to Moses about Jesus (the coming prophet). God gave Moses the reason why him being a man is nessessary.
"For this is what you asked of the Lord your God at Horeb on the day of the assembly when you said, “Let us not hear the voice of the Lord our God nor see this great fire anymore, or we will die. The Lord said to me: “What they say is good. I will raise up for them a prophet like you from among their fellow Israelites, and I will put my words in his mouth. He will tell them everything I command him. I myself will call to account anyone who does not listen to my words that the prophet speaks in my name." - Deut 18:16-19
We know this scripture is referring to Christ as Peter quoted it in Acts 3 and Stephen in Acts 7.
Clearly, no one can sit at the feet of God and gaze upon him or hear his voice and live. He made this clear in Exodus 33:20, "you cannot see my face, for man shall not see me and live.” God has put his authority in His man Messiah, whom man can gaze upon, and we are to listen to everything he tells us and see it as coming directly from God himself.
Notice also in verse 17 how God would raise up the Messiah "from among their fellow Israelites." This agrees with Genesis 3 that he would be from eve's seed and a descendent of Abraham and David as Matt 1:1 states. He would be a son of Man, in other words, a human being.
"Though he were a son, he learned obedience from what he suffered and, once made perfect, he became the source of eternal salvation for all who obey him." - Heb 5:7,8
When you turn Christ into God, you put him out of our reach and remove all of his humanity. It's a blessing to know the truth about Christ and see him as our human example. We as humans are capable of obeying God just as he was.
"Praise be to the God and Father of our Lord Jesus Christ, the Father of compassion and the God of all comfort" - 2 Cor 1:3