Humanity; all of us, can be so excited about a person, event, or miraculous happening one moment, and the next turn our hearts and mind against it. I believe that is called “fickleness”.
There were some people in Jesus’s day who wanted to make Him King when they heard Him teach and saw His miracles (John 6:15).
Today people are still moved by the spectacular. Given to thrilling events. Why do you think people watch High wire acts, or jumping motorcycles, or high speed races at Daytona, or Indianapolis; and other such races. We can be fans of a racer one minute, then in a heartbeat turn against him or her. That is true, not just of racing, but in other areas of life. Look at what John has written of Jesus and people in His day,
“Now when He was in Jerusalem at the Passover, in the feast day, many believed in His name, when they saw the miracles which He did. But Jesus did not commit Himself unto them, because He knew all men, and needed not that any should testify of man: for He knew what was in man.” John 2:23-25 (KJV)
We have several accounts in the Gospel where people were drawn to Jesus to see His miracles and signs, and were awed by them, and Him. “Many believed in His name”, but they were believing simply because of what they seen Him do. They were not believing in Him fore who He is.
That is why it says that “Jesus did not commit Himself unto them”. He knew what was in men. He knows that we are fickle. At the time when we are told they wanted to make Him king; Jesus goes to the mountain to pray. Why? Most likely because it was not His time to be made King. He had another work to do.
He probably also knew that it would be some of these same people who flocked to see His signs and miracles that would cry out later, “Crucify Him, crucify Him”. He knows what is in man. He knows what is in you. He knows what is in me.
Yet He was willing to go all the way to the cross to die for our sins. When we truly commit ourselves to Him, believing He is the Christ Son of the Living God, and God the Living Son, then, He gives us a new heart, mind, and His strength for life and living.