John 5:18 Therefore the Jews sought the more to kill him, because he not only had broken the sabbath, but said also that God was his Father, making himself equal with God.
John 5:19 Then answered Jesus and said unto them, Verily, verily, I say unto you, The Son can do nothing of himself, but what he seeth the Father do: for what things soever he doeth, these also doeth the Son likewise.
John 5:20 For the Father loveth the Son, and sheweth him all things that himself doeth: and he will shew him greater works than these, that ye may marvel.
Jesus claims that God shows Him all things that He does. According to the dictionary, to “do” means to engage in. So, if I engage in thought then I’m doing something called thinking. The Bible informs us that when God swears by Himself he uses the phrase “As I live”; yet, since God is not a man, the verb “live” is taken as an anthropomorphism or a metaphor that points to the fact that God thinks or engages in thought. In this way, the bible and the dictionary agree that thinking is doing; therefore, since thinking is something that God does, then from the John 5:20 sentence we must deduce that EVERYTIME God thinks, God is showing Jesus what He is thinking; consequently Jesus knows the mind of God.
In fact, in order to know ALL things that God the Father does including the things that God will do in the future (as verse 20 states), Jesus would have to have the mind of God. So we see that it is not possible to make the claim to know ALL the things that God is doing or will do without actually knowing the mind of God. With all of this in mind, the bible in Isaiah 40:13, Romans 11:34 and 1 Corinthians 2:16 asks the following rhetorical question: Who has known the mind of God? After converting this sentence from the interrogative mode to the declarative mode (as the biblical context requires us to) we arrive at the proposition that NO ONE has known the mind of God! Yet, Jesus claims this exact divine prerogative. What else can be concluded except that Jesus must be God. In fact, if Jesus is not God, then these verses suggesting that no one has known the mind of God are erroneous.
Additionally, since God knows everything and is unceasingly disclosing to Jesus ALL that He is thinking, then it follows that Jesus must be omniscient; a characteristic that only belongs to God. The bible scholar Albert Barnes commenting on this verse states: And as God shows him “all” that he does, he [Jesus] must be possessed of omniscience, for to no finite mind could be imparted a knowledge of “all” the works of God.
In summary, claiming to know the mind of God and asserting omniscience are outright declarations that one is God. Jesus makes these declarations ergo He claims that He is God.