Sometimes the truth is too hard to believe. Jesus was making claims of Himself that were beyond belief to those who knew Him.
In John 6:41-42 we read: The Jews then complained about Him, because He said, “I am the bread which came down from heaven.” And they said, “Is not this Jesus, the son of Joseph, whose father and mother we know? How is it then that He says, ‘I have come down from heaven’?”
Jesus was making an incredible claim beyond their understanding. How could He say that “I have come down from heaven,” when they all knew Him and His parents and when He was born. Their logical conclusion was that Jesus was misspeaking. This couldn’t be true so therefore Jesus must be lying or crazy. This is always the reaction of the uninspired who look upon Christ with unbelief.
Jesus stood with them, walked with them, talked with them but He hadn’t been revealed to them. Without the divine initiative at work they would never understand. This is still the case, you must by faith accept Jesus Christ without requiring that you see or touch Him. Jesus is the bridge between the natural and the spiritual. He came from above, being made a man becoming God in the flesh. They could see Jesus and touch Him and hear Him, but they couldn’t comprehend Him beyond the flesh. That, is where faith enters in; we must by faith receive Christ and then the gap between our natural understanding and spiritual reality is filled. If God has revealed Himself to you, respond in faith and all these things will become clear. You will come to know Jesus Christ for who He really is, our Savior and Lord.