Oneness Doctrine ver Trinity Doctrine

I am a Trinitarian, so naturally I oppose the resolution. First, I would like to provide some definitions. Oneness Doctrine: "[The] Oneness [doctrine] describes God as only one primary entity, with possibly three “manifestations. ”" [1]Trinity Doctrine: "The [Trinity] doctrine states that God is the Triune God, existing as three persons, or in the Greek hypostases, but one being" [2]I will first address my opponent's arguments before raising arguments of my own. Rebuttal:Pro writes "From Genesis to Revelations, the Bible simply states that God is one, and not two or three. Subject and verb agreements must agree in number, and if you study the Bible carefully, the subject " God, " is always followed by the singular verb " is ". "I reply "However, plural verbs are applied to God, as well as plural adjectives. Also, plural pronouns are used to represent God. A striking example of this is Genesis 1:26 'Then God said: "Let us make man in our image, after our likeness. ' (emphasis mine). Similar plurality can be found in Genesis 3:22, Genesis 11:7, and Isaiah 6:8. Also, the word used to refer to God in the Old Testament, Elohim, is in the plural form. "While my opponent says much more in his argument, I don't really see much of it besides the bit I quoted pertaining to the Trinity Doctrine vs the Oneness Doctrine, so I haven't responded to it, because Trinitarians believe Jesus to be God. My Case:1. The Father, Son, and Holy Ghost in one formulaIn 2 Corinthians 13:13, we see 'The grace of the Lord Jesus Christ and the love of God and the fellowship of the holy Spirit be with all of you. '. What's the point of that if the Trinity does not exist? Why not just say 'The grace, love, and fellowship of God be with all of you'? Similarly, we have Matthew 28:19, which says 'Go, therefore, and make disciples of all nations, baptizing them in the name of the Father, and of the Son, and of the holy Spirit,'.2. Mentions of the Father, Son, and Holy Ghost as distinct personsActs 7:55 reads 'But he, filled with the holy Spirit, looked up intently to heaven and saw the glory of God and Jesus standing at the right hand of God,'. How does Jesus stand at his own right hand, if he is the only divine person? Matthew 3:16-17 reads '(16) After Jesus was baptized, he came up from the water and behold, the heavens were opened (for him), and he saw the Spirit of God descending like a dove (and) coming upon him. (17) And a voice came from the heavens, saying, "This is my beloved Son, with whom I am well pleased. "" Why would Jesus say that he is his own son? In fact, the entire bit of Jesus being the Son of God doesn't make much sense if Jesus is the only divine person. Luke 22:41-42 says '(41) After withdrawing about a stone's throw from them and kneeling, he prayed, (42) saying, "Father, if you are willing, take this cup away from me; still, not my will but yours be done. "' Why would Jesus pray to himself? At many points in the New Testament, Jesus, the Father, and the Holy Spirit are mentioned ways that don't make sense if they are all just "manifestations", as they seem to interact with one another in ways that make them seem like distinct beings. But we know there is only one God. Therefore, to reconcile this, the doctrine of the Trinity was created as early as the third century. God is one in three divine and distinct persons. I turn it over to my opponent. Sources:1. Some random website2. . http://en.wikipedia.org...3. . http://www.vatican.va...