The book of Revelation opens with the following line:
Revelation 1:1 (WEB)
1 This is the Revelation of Jesus Christ, which God gave him to show to his servants the things which must happen soon, which he sent and made known by his angel to his servant, John,
Notice above that Jesus has relayed a revelation to John, which "God gave Him". Consider this from a Trinitarian perspective. Does God "give" God a revelation, and instruct God to show it to others? What exactly does it mean for a single Being to "give" something to another Person within His same Being? Does that preserve any meaningful definition of "Being", if there is one subject speaking to another, and giving another a "revelation" to pass on, all allegedly within one "Being"? It seems like there are clearly multiple minds, and multiple selfs, which do not share the same information, as one can direct another to do things.
But the above verse is far from the only place in which John presents Jesus as getting revelation from God. Repeatedly in John's Gospel, Jesus says that the message that He was preaching was not His own, but given to Him by God:
John 7:16-18 (WEB)
16 Jesus therefore answered them, "My teaching is not mine, but his who sent me.
17 If anyone desires to do his will, he will know about the teaching, whether it is from God, or if I am speaking from myself.
18 He who speaks from himself seeks his own glory, but he who seeks the glory of him who sent him is true, and no unrighteousness is in him.
John 8:28 (WEB)
28 Jesus therefore said to them, "When you have lifted up the Son of Man, then you will know that I am he, and I do nothing of myself, but as my Father taught me, I say these things.
John 12:49-50 (WEB)
49 For I spoke not from myself, but the Father who sent me, he gave me a commandment, what I should say, and what I should speak.
50 I know that his commandment is eternal life. The things therefore which I speak, even as the Father has said to me, so I speak."
John 14:10 (WEB)
10 Don't you believe that I am in the Father, and the Father in me? The words that I tell you, I speak not from myself; but the Father who lives in me does his works.
Also see John 3:34, 17:8.
Notice the strength and consistency with which Jesus denies preaching His own message, and instead, how He says that He is giving a message that has been given to Him from God. Under a Trinitarian view of God, or one in which Jesus is God, these statements become astounding puzzles, which strain the mind to conceive of how they could be anything other than deception. If Jesus is in fact God, then every last word He spoke did come from Himself. If Jesus is in fact God, then His message was His own. If Jesus is God, then the Father is His very same Being, and under most classical understandings, even has the very same mind, and will. Such a situation would turn these into very strange statements indeed - ones whose meanings can only be determined under an edifice of developed Trinitarian theology, and even then, with difficulty.
Or, they can be taken to mean that the Messiah, who is not God, received a message from God, and faithfully preached that message, even under persistent persecution. And, as the passage from the book of Revelation shows, God has continued to give revelation to Jesus, even after His earthly life, as He occupies His exalted position.
Consider which suggested understanding of these passages is more clear. Think carefully on which interpretation makes these passages plain, and understandable, and which one turns them into a puzzle. Ask whether a statement like Revelation 1:1 - the opening sentence to a book - is implied in its context to be a very mysterious saying, into which the reader is to read all of the implied theology which Trinitarianism requires in order for it to make sense. Trust that Jesus is able to say that His message did not come from Himself, and have that mean simply what it appears to mean - it came from another, namely, God.