Right on the heals of Jesus claiming to be God by applying the Divine Name to himself, Jesus actually performs an act to show that he is God. This is immediately following the confrontation with the religious authorities. Jesus departs from there and this scene unfolds:
As he walked along, he saw a man blind from birth. 2 His disciples asked him, ‘Rabbi, who sinned, this man or his parents, that he was born blind?’ 3 Jesus answered, ‘Neither this man nor his parents sinned; he was born blind so that God’s works might be revealed in him. 4 We must work the works of him who sent me while it is day; night is coming when no one can work. 5 As long as I am in the world, I am the light of the world.’ 6 When he had said this, he spat on the ground and made mud with the saliva and spread the mud on the man’s eyes, 7 saying to him, ‘Go, wash in the pool of Siloam’ (which means Sent). Then he went and washed and came back able to see.
Many people focus on the disciples’ illogical question of whether this man sinned before he was born so that he was born blind. There are historical and cultural reasons why they asked such a question, but leaving that aside, the real issue is the miracle. Jesus just claimed I Am as his name. Now here is a person who was born without the ability to see. He was born without eyes, as it were. So Jesus does what I Am would do–he takes dust from the ground and creates what was missing in this man’s body. Just as God took dust from the ground and created humanity originally, Jesus does the same thing to complete this man’s creation and give him sight.
This is the reason why the religious leaders deal with this miracle so much more than they did any other miracle Jesus performed, with the possible exception of raising Lazarus from the dead, and even then Jesus gives life which is something only God can do. Jesus said he was God, and now he proved he was God by his actions. Those who would deny Jesus is God are not reading the plain meaning of the text, but rather have preconceived notions about Jesus and try to make the Bible fit into their understanding, rather than let the biblical witness to Jesus inform who Jesus is.