It is a fact that most Christians claim that Jesus is God, while at the same time it is a fact that the Bible, specifically the first chapter of John says that we cannot see God, as the passage clearly says:
15 John bare witness of him, and cried, saying, This was he of whom I spake, He that cometh after me is preferred before me: for he was before me. 16 And of his fulness have all we received, and grace for grace. 17 For the law was given by Moses, but grace and truth came by Jesus Christ. 18No man hath seen God at any time(John -18)
So as you can see, the Gospel of John is making it very clear that God cannot be seen, and that no man has ever seen God, what makes this very interesting is that just a few passages later he writes:
29 The next day John seeth Jesus coming unto him (John )
So we are told by John that no man has seen God, John is a man, and John says he saw Jesus, therefore logic tells you that Jesus is not God nor did John believe he was. Does it make sense for John to believe that Jesus is God when he said that no man has seen God, and then a few passages later say I saw Jesus? It is clear that John did not see Jesus as God, or else he would not have said no man has seen God and then say I saw Jesus. It would be an obvious contradiction of John if he believed Jesus is God after saying no man has seen God at any time.
In fact let us see what John had to say concerning Jesus, continuing with passage 29:
29 The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world
Notice John calls Jesus the lamb of God, he did not say behold God is here! Which is clear, he does not believe Jesus is God in the first place, which is why he made it clear that no man can see God.
John continues the first chapter of the Gospel writing:
37 And the two disciples heard him speak, and they followed Jesus. 38 Then Jesus turned, and saw them following, and saith unto them, What seek ye? They said unto him, Rabbi, (John -38)
Further proof from John that he does not believe that Jesus is God, he is telling us a story of Jesus being called a rabbi, obviously a rabbi is not God, it is clear that John believes that Jesus is a teacher, and prophet, a rabbi you could say.
So in conclusion Jesus cannot be God since John made it clear that no man can see God, since John saw Jesus, Jesus is not God. Very simple.