Ever notice there are expiration dates on almost everything? This is especially true of the food we buy to eat; from a few days for a bag of salad, to a couple of weeks for a gallon of milk, to even years for some dried and canned foods. We live in a world of perishing things. Even the things we label "non-perishable" ultimately decay, rust, fade and age in one way or another. It's interesting how much we can come to desire and even love stuff that will not stand the test of time.
In the sixth chapter of John's gospel, the Bible tells us that the very next day after Jesus had miraculously fed 5000 men plus the women and children, the crowds were back for more. In John 6:26 Jesus plainly tells them that they were seeking Him more for the food than anything else. Jesus had become something of a miracle-producing vending machine to many in the multitude following Him. They were missing the spiritual and eternal truths Christ had been preaching to them. They were especially missing who it was who had come among them, namely the eternal Son of God.
Jesus wanted those hearing Him to get to work. The word "labor" in the above verse basically means employment; like a farmer at work in his field (plowing, planting, harvesting, and so on). Get the picture the Lord was painting for them? He wanted them to see that the physical things of this world that we desire so dearly and invest so much of our lives in will eventually come to nothing. What they needed were the teachings and the person of Jesus Himself. The prophet Isaiah put it this way:
"Why do you spend money for what is not bread, and your wages
for what does not satisfy? Listen carefully to Me, and eat what is
good, and let your soul delight itself in abundance." (Isaiah 55:2)
Obviously we need material things to survive in this world; food, shelter, clothing and such. Isaiah 55:2 would have us see that the material should not captivate and absorb us to the exclusion of all else-especially God. What God is saying is, "do not apply all your energies or give first place to material things and the pursuit of them." The material things of this world do not satisfy for long for they perish. Likewise, we too will physically perish one day; we have a physical expiration date. John 6 would have us focus on the spiritual and the eternal. Don't buy what lasts for a season. Invest in what will never wear out; believe in the One whom God sent, Jesus Christ.