Keep in mind, the man has no idea what Jesus looks like. Here’s the interaction the Apostle John records.
Jesus heard that they had cast him out and having found him he said, “Do you believe in the Son of Man?” He answered, “And who is he, sir, that I may believe in him?” Jesus said to him, “You have seen him, and it is he who is speaking to you.” He said, “Lord, I believe,” and he worshiped him. John 9:35-38
In his mind, Jesus went from being simply a man, to a messenger from God, to a miracle worker, and finally Lord. Think for a moment: if he would have just received his sight, physically he would have been much better off. Spiritually though, he would still be blind. He would have tried, like so many others, to do good deeds to earn God’s eternal favor. The restoration of sight would have given him the ability to learn a trade, find a wife, raise a family, and be a contributing member of society, but his spiritual blindness would have remained. Grace saved him from physical darkness, but he needed to be saved from the eternal darkness of Hell (Matthew 8:12). Jesus did more than just give physical sight, He illuminated the man’s spiritual eyes.
So why was he born blind? It wasn’t something his parents or he had done wrong, but what God had done. God tells Moses in Exodus 4:11, “Who has made man’s mouth? Who makes him mute, or deaf, or seeing, or blind? Is it not I, the Lord?” This man was born blind for the expressed purpose of bringing glory to God! And that glory was seen not just in the miracle of healing, but most powerfully in the man’s salvation prayer, “Lord, I believe.” Absolutely everything exists and happens for a reason. What reason? – God’s glory.
Glory is about honor, splendor, and majesty. When an athlete wins a gold medal or a team wins a championship, they experience the glory of victory. Imagine an athlete or team winning and the trophy being handed over to the second or last-place team. It would be wrong. The glory of the gold medal belongs to the winner. They are placed on the highest platform and only their anthem is played. This is why worshiping and giving glory to other gods is so grievous to the one true God. He and He alone deserves the glory. The Bible calls this idolatry or spiritual adultery. Idolatry gives credit and honor that belongs only to God to another.
I am the Lord; that is my name; my glory I give to no other, nor my praise to carved idols. Isaiah 42:8