“Do not work for the food which perishes, but for the food which endures to eternal life, which the Son of Man will give to you, for on Him the Father, God, has set His seal.” John 6:27 (NASB)
We are not to labor only for the things that satisfy the body. It is honorable to work for food and clothing, but we are to look beyond physical needs and put spirit and soul first. “Do not work” is negative, but there is a positive side here, too: we are instructed to work for spiritual food–“for the food which endures to eternal life.”
This does not pertain to redemption (only the blood of Jesus redeems). It means that we are to be laborers together with Christ, good soldiers, faithful stewards. If we only obey the negative part of the command and “do not work” exclusively for things that perish, and then obey the positive part of the command and strive earnestly for things that satisfy the spirit and soul, we have a divine promise: Jesus will provide that which satisfies, spiritual food that endures forever and brings everlasting life.
For on Him the Father, God, has set His seal” is a declaration that Jesus Christ is the only one appointed by God to give this spiritual food. He is the sole dispenser of spiritual bread, spiritual meat, spiritual milk and spiritual drink. Actually, the reference is to the custom of setting apart a person for a specific ministry or mission. In the Old Testament we read, “Now you write to the Jews as you see fit, in the king’s name, and seal it with the king’s signet ring; for a decree which is written in the name of the king and sealed with the king’s signet ring may not be revoked.” Esther 8:8 (NASB)
The statement here, in John 6:27, signifies that in the eternal ages behind us, before the world was, in the eternal councils of God the Father, God the Son, and God the Holy Spirit, the Father appointed, commissioned, and sealed the Son, the Word Incarnate, to be the sole giver of everlasting life. The office Jesus occupies was set apart for Him by God the Father, and He is the only one who can fill that office. He is seated at the right hand of the Majesty; He earned that position because He finished the work the Father gave Him to do. He fulfilled the law and the prophets, and satisfied the righteousness and holiness of God.
The miracle of the loaves and fishes (John 6:1-15) had prepared the way and set the stage for Jesus to announce Himself as the bread of life, and He began that announcement by telling the Jews not to labor for things that perish, but for the things of the Spirit, things that lead to everlasting life.