The nature of Christ, is off-topic... because that would only add 9 more pages to the conversation. I quick rundown
The fundamental teaching in the Old Testament that God is one, the Jews always believed that God is numerically one and no-where did that change. God took on humanity and existed as a human, felt, eat, slept, died and even had an relationship with God.
1 Timothy 3:16
16 And without controversy great is the mystery of godliness:
God was manifested in the flesh,
Justified in the Spirit,
Seen by angels,
Preached among the Gentiles,
Believed on in the world,
Received up in glory.
The term "God the Father" is biblical and refers to God Himself (Galatians 1:1-4). God is the Father; He is not merely Father of the Son, but the Father of all creation (Malachi 2:10; Hebrews 12:9). He is also our Father by reason of the new birth (Romans 8:14-16). The title Father indicates a relationship between God and man, particularly between God and His Son and between God and regenerated man. Jesus taught many times that God is our Father (Matthew 5:16, 45, 48). He taught us to pray, "Our Father which art in heaven" (Matthew 6:9). Of course, Jesus as a man had an additional relationship to God in a sense that no one else has ever had. He was the only begotten Son of the Father (John 3:16), the only One who was actually conceived by the Spirit of God and the only One who had the fulness of God without measure.
The Bible plainly states that there is only one Father (Malachi 2:10; Ephesians 4:6). It also clearly teaches that Jesus is the one Father incarnate (Isaiah 9:6; John 10:30). The Spirit that dwelt in the Son of God was none other than the Father.
The Holy Spirit is simply God. God is holy (Leviticus 11:44; I Peter 1:16). In fact, He alone is holy in Himself. God is also a Spirit (John 4:24), and there is only one Spirit of God (I Corinthians 12:11; Ephesians 4:4). Therefore, "Holy Spirit" is another term for the one God.
Hebrews 5:7
7 who, in the days of His flesh, when He had offered up prayers and supplications, with vehement cries and tears to Him who was able to save Him from death, and was heard because of His godly fear,
As a man he held to an separate consciences from God. So as the son he was completely human had no power and lived as a man, even prayed as a man. (in His flesh)
I do NOT believe in the Trinity, I don't believe the apostles believed in the Trinity and that it is bad logic. It was developed 325 years after Christ by "church" councils. The Holy Spirit didn't become deified until much later...
Definition of the Trinity - God is three separate and co-equal beings. (The Father, Son, and Holy Spirit are three separate and co-equal beings)
God is not three but God is one - not a compound unity but a absolute unity (always has been).
"Hear, O Israel: the LORD our God is one LORD" (Deuteronomy 6:4).
LORD in all caps was the word that adonai was used in the place of YHWH because of the fear of taking the name of God in vain, the stop saying it at all and replaced it with adonai meaning lord.
"2 Now a mediator does not mediate for one only, but God is one." (Galatians 3:20).
"Before me there was no God formed, neither shall there be after me. I, even I, am the LORD; and beside me there is no saviour" (Isaiah 43:10-11).
"I am the first, and I am the last; and beside me there is no God" (Isaiah 44:6).
"Is there a God beside me? yea, there is no God; I know not any" (Isaiah 44:8).
"I am the LORD that maketh all things; that stretcheth forth the heavens alone; that spreadeth abroad the earth by myself" (Isaiah 44:24).
"There is none beside me. I am the LORD and there is none else" (Isaiah 45:6).
"There is no God else beside me; a just God and a Saviour; there is none beside me. Look unto me, and be ye saved, all the ends of the earth: for I am God, and there is none else" (Isaiah 45:21-22).
"Remember the former things of old: for I am God, and there is none else; I am God, and there is none like me" (Isaiah 46:9).
"I will not give my glory unto another" (Isaiah 48:11; see also Isaiah 42:8).
"O LORD of hosts, God of Israel, that dwellest between the cherubims, thou art the God, even thou alone, of all the kingdoms of the earth: thou hast made heaven and earth" (Isaiah 37:16).
There is only one God, who is the Creator and Father of mankind (Malachi 2:10). In the time of the Millennial Reign, there shall be only one LORD with one name (Zechariah 14:9).
"Seeing it is one God which shall justify" (Romans 3:30).
"There is none other God but one" (I Corinthians 8:4).
"But to us there is but one God, the Father" (I Corinthians 8:6).
"But God is one" (Galatians 3:20).
"One God and Father of all" (Ephesians 4:6).
"For there is one God" (I Timothy 2:5).
"Thou believest that there is one God; thou doest well: the devils also believe, and tremble" (James 2:19).
Again, the Bible calls God the Holy One (I John 2:20). There is one throne in heaven and One sits upon it (Revelation 4:2).
The Old Testament speaks of God in terms of being one. Many times the Bible calls God the Holy One (Psalm 71:22; 78:41; Isaiah 1:4; 5:19; 5:24), but never the "holy two, the holy three," or the "holy many."