“Meanwhile, the disciples were urging him, ‘Rabbi, please have something to eat!’ But he said to them, ‘I have food to eat you fellows know nothing about!’ So the disciples were saying to each other, ‘You don’t think somebody brought him something to eat while we were away, do you?’ Jesus says to them, ‘My food is to do the will of the One Who Sent Me and to complete his mission.'” (John 4.31-32)
Fulfilling work, we learn from Jesus’ remark, is physically full-filling. When one feels one’s work is the very will of God, Jesus seems to be suggesting, one feels even physically nourished in body, not to mention what such a conviction does to soul and spirit. Jesus is teaching his disciples here to find the will of God for one’s work and in one’s work, and that this finding feeds, even physically.
A wag once said that every time one goes to the refrigerator one is looking for God. What he meant is that sometimes life is so unfulfilling that only food (or drink or drugs) can satisfy the soul, not to mention the body. (Might our passage address addictions?) An antidote to addiction is fulfilling work. One fruit of this passage for Christian readers is the provocation of questions such as: Am I in the will of God? Do I have even a physical sense of the satisfaction my work can bring? What vocational decision should I make to be “filled”? (“Do a thorough moral inventory.” The Twelve-Step Programs, founded on Christian premises by the Rev. Samuel Shoemaker and Bill W. – have been deply helpful in raising basic questions like these.)
In our story Jesus is now the model Christian worker. He has already taught us the basics of Christian Evangelism (vv. 7-15) and of Christian Worship (vv. 16-26). He is now teaching us the basics of Christian Work or Mission (vv. 27-42). The fulfilling will of The One Who Sent Jesus does not need to be direct evangelism. “Are all evangelists?” asked Paul in effect (1 Cor. 12.19; cf. Eph. 4.11). The fulfilling will of The One Who Sent Jesus is to be about the work for which God gifted one in creation and for which God calls one in Jesus’ re-creation of his people into New Life. The Reformation doctrine of vocation taught disciples to find in their humblest work the highest service of God and neighbor.
Jesus’ earlier vocational teaching in the Synoptic Gospels (often in connection with his disciples’ all-too-human quest for “greatness” or recognition) taught disciples to find their greatness and their greatest satisfaction in service, in going down. I believe our present text is the Johannine equivalent of Jesus’ Synoptic texts and is saying, quite simply: “You will find that doing the will of God is even the most physically satisfying way to live.”
Frederick Dale Bruner, The Gospel of John: A Commentary (Eerdmans, 2012), pp.274