Where Did the Trinity Teaching Come From?

[Neo-Scholastic]

At John 17:1, it says Jesus was praying to the Father. Since Jesus and Jehovah are supposedly the same god within the fabricated "Godhead," am I supposed to conclude that God was praying to himself?

Jesus also prayed to the Father from the Cross. About the ninth hour Jesus cried out in a loud voice, "Eloi, Eloi, lama sabachthani?"--which means, "My God, my God, why have you forsaken me?" (Matt 27:46)

The paradox of praying to himself appears only when you ignore the fact that Jesus of Nazareth was God manifest in the flesh. Thus for that brief time in history our Lord expressed himself through two natures: both visible (the image) and invisible (YHVH). In his flesh he shared an outward humanity, prone to pain, suffering, and despair, but inwardly he was divine which gave him the power to overcome. Those conflicting natures were resolved when he died on the cross. Glorification refers to the process whereby our Lord sheds his humanity and becomes fully divine. Thus it was the humanity that prayed, not a separate divine person, as he called on the love inside himself to triumph. This interpretation is further supported by the passage I quoted earlier:

Do you not believe that I am in the Father, and the Father is in Me? The words that I say to you I do not speak on My own initiative, but the Father abiding in Me does His works. (John 14:10)

The Father being something within Jesus is further supported by another earlier passage from John:

No one has taken it away from Me [his life], but I lay it down on My own initiative. I have authority to lay it down, and I have authority to take it up again. This commandment I received from My Father. (John 10:18)

If Jesus lays down his own life on his won initiative than how can he also say he was commanded to do so by a separate entity. It is the Father, the divine love, within Jesus that drives him toward the Passion. We experience a similar duality when we say that we are ‘of two minds’, until that is, we make our decision. Then there is no longer the same duality; our consciousness is no longer as of two. Christ joins his humanity to his diety so they are united in purpose. His earthly doubt disapears and there is no more separation between heaven and earth. When his work was finished his humanity was glorified and made perfect,

John 17:1, Jesus said in prayer to Jehovah: "glorify your son, that your son may glorify you." If Jesus and Jehovah are the same god … Individually glorifying each other raises a red flag that these are two separate and distinct persons; otherwise, this glorifying of each other would make no logical sense.

See above.

At John 17:25, Jesus said to Jehovah: "Righteous Father…,I have come to know you…." Am I supposed to believe God was having a conversation with himself during which one part of God was telling the other part that God came to know himself?

Once again Jesus shared in our humanity. His authority over evil resulted from his facing and overcoming all the temptations we ourselves face. Like us he felt conflicted between the urges of the flesh and the love inside him.

At John 17:25, Jesus said to Jehovah: " you sent me forth…." …The rules of hierarchy dictate that the one being sent forth is inferior to the one doing the sending. Throughout the scriptures, Jesus is shown taking instructions from Jehovah. It is never the other way around. So what happened to co-equality within the fabricated Trinity "Godhead"?

Your error is making God into a finite being who is located in just in one place, and nowhere else. God fills heaven and earth. Thus he also fills the humanity of Jesus like the soul fills the body. Likewise, our Lord is in us when we receive him into them. When the Words talk about ascending and descending, it sounds as if he travels around from place to place. This is merely an appearance. With respect to the Son, it just means our Lord took on a visible form. It was not another person that sent him, he sent himself. That is the meaning of the following verses:

No one has ascended into heaven, but He who descended from heaven: the Son of Man. (John 3:13) and And Jesus cried out and said, “He who believes in Me, does not believe in Me but in Him who sent Me. He who sees Me sees the One who sent Me. (John 12:45)