Do not work for food that spoils, but for food that endures to eternal life, which the Son of Man will give you. On him God the Father has placed his seal of approval.
In this passage, Jesus is contrasting the crowd's desire to attain food that perishes with the food that He says will give eternal life. Jesus is advising the crowd in a spiritual sense, not to search for earthly things (represented by the food that goes bad) but rather put their faith and trust into Jesus, who will never perish.
The "food that endures to eternal life" can be interpreted much like the "living water" that Jesus offers the woman at the well in John 4. He is offering her something that will not evaporate with the heat, but the water that can satisfy her soul.
A relationship with Jesus is the outcome of us accepting the Bread of Life or the Living Water. When we put our faith and trust into Jesus Christ, it results in us having a special and personal relationship with Him. So the "Bread of Life" does not mean having a relationship with Christ, but rather that relationship with Him is the result when we "work for the food that that endures to eternal life".
[Answered by Pastor Kelly]
