John 10:38, "That ye may know and believe that the Father is in me, and I in Him." The same is repeated in chapter 14:11. In chapter 17:21, it is said, "That they all may be one, as thou, Father, art in me, and I in Thee, that they also may be one in us; that the world may believe that Thou hast sent me. And the glory which Thou gavest me, I have given them, that they may be one even as we are one. I in them, and Thou in me, that they may be made perfect in one," etc.
The junction of Father and Son is conferred also upon the twelve apostles. If, therefore, the Christians thought it necessary to change their belief in the Divine unity, they were not justified in adopting the term "Trinity," inasmuch as the twelve apostles are placed on an equality with Jesus, and they might, with the same latitude of argument, be well included in the coalition of Divine personages.
This is an area where I have good agreement with Troki. In John 10, Jesus confronts the Jewish authorities. The crowds challenge him to proclaim himself as Messiah, but Jesus does one better than that. He says "I and the Father are one." The crowds then accuse him of blasphemy, for who could be unified with God but God? Mohammad was quite right to assume that no creature could assume partnership with our Creator, and that seemed to reflect Second Temple Jewish sentiments as well.
Troki argues that in Chapter 17, Jesus says that the disciples are to be one, just as the Son and Father are one. Therefore, Jesus' claim to be one with the Father is not a claim of deity. This, I think, is to misunderstand the passage. Jesus did claim to be one with the Father in the sense that he wanted the disciples to be one. In John 17 Jesus gives his high priestly prayer over his disciples, desiring that they would be united in their mission. Jesus claims that his own mission with the Father is one of the same unity. Jesus and the Father are one in their mission to redeem humanity, bringing about salvation. Jews knew that only God is the source of salvation, and this sentiment is still in the siddur to this day.
The kicker is the Jewish reaction. Why stone Jesus for blasphemy if he was only claiming to be an important prophet or exalted creature? Claiming to be Messiah is not blasphemy. Claiming to be exalted is not blasphemy. Claiming to be God, however, is grounds for being stoned. And if that isn't enough, remember verse 33:
The Jews answered him, “It is not for a good work that we are going to stone you but for blasphemy, because you, being a man, make yourself God.”