{5} Jesus answered and said unto them, {g} This is the work of God, that ye believe on him whom he hath sent.

(5) Men torment themselves in vain when they try to please God without faith.

(g) That is, this is the work that God requires, that you believe in me, and therefore he calls them back to faith.

People's New Testament

6:29 This is the work of God, that ye believe on him whom he hath sent. They are startled by hearing that to please God the first requirement is faith in Christ. This is the work of God that pleases him. Without faith it is impossible to please God (Heb 11:6). It is not works, but one work, that is required, a faith that would enable them to lay hold upon him who is the Bread of Life. From such faith would spring a Christlike life.

Wesley's Notes

6:29 This is the work of God - The work most pleasing to God, and the foundation of all others: that ye believe - He expresses it first properly, afterward figuratively.

Jamieson-Fausset-Brown Bible Commentary

29. This is the work of God-That lies at the threshold of all acceptable obedience, being not only the prerequisite to it, but the proper spring of it-in that sense, the work of works, emphatically "the work of God."

Matthew Henry's Concise Commentary

6:28-35 Constant exercise of faith in Christ, is the most important and difficult part of the obedience required from us, as sinners seeking salvation. When by his grace we are enabled to live a life of faith in the Son of God, holy tempers follow, and acceptable services may be done. God, even his Father, who gave their fathers that food from heaven to support their natural lives, now gave them the true Bread for the salvation of their souls. Coming to Jesus, and believing on him, signify the same. Christ shows that he is the true Bread; he is to the soul what bread is to the body, nourishes and supports the spiritual life. He is the Bread of God. Bread which the Father gives, which he has made to be the food of our souls. Bread nourishes only by the powers of a living body; but Christ is himself living Bread, and nourishes by his own power. The doctrine of Christ crucified is now as strengthening and comforting to a believer as ever it was. He is the Bread which came down from heaven. It denotes the Divinity of Christ's person and his authority; also, the Divine origin of all the good which flows to us through him. May we with understanding and earnestness say, Lord, evermore give us this Bread.