Jesus accuses the crowd of coming to find Him simply because they were fed! It brings up an interesting point. We understand that He did a miracle with the loaves and the fish, but how many outside of the circle of disciples would know? Jesus encourages them to not just look for literal food, but spiritual food: the food that only He can provide. They want Him to be the prophet like Moses, and to perform a miraculous sign like the manna. Were they looking for daily feeding, or for something more spectacular than loaves and fish? Either way, Jesus cautions them that it was God who actually did the miracle, and He was currently doing another one in their midst. They just need to believe that Jesus is the bread of life!
This is the first of seven “I am” metaphors in the book of John. Jesus is using the title that God used for Himself in Exodus 3:14. Not only is Jesus claiming deity here, but He is sharing with them that He is the giver of eternal life. They have to believe in Him (eat of His flesh), because He is going to give His body on the cross for the sake of mankind. They can believe if the Father brings them through the Spirit, and Jesus will accept them because that is the Fathers will. Once they are accepted they will be His for eternity, and will participate in the bodily resurrection at the end of the age!
Some of the crowd find this hard to understand. They take his metaphor literally, and don’t understand that He is foreshadowing His death on the cross. They quit following Him at this point, but the disciples understand that Jesus has “the words of eternal life.” However there is one among the 12 who does not believe. John makes sure to record Jesus comments about Judas here to again emphasize that Jesus knows and understands all things, and that what was foretold in the OT must take place.
For worship: https://www.youtube.com/watch?v=tdxSC1tHJn0