John 6:29

Jesus answered and said unto them, this is the work of God,
&c.] The main and principal one, and which is well pleasing in his sight; and without which it is impossible to please him; and without which no work whatever is a good work; and this is of the operation of God, which he himself works in men; it is not of themselves, it is the pure gift of God:

that ye believe on him whom he hath sent;
there are other works which are well pleasing to God, when rightly performed, but faith is the chief work, and others are only acceptable when done in the faith of Christ. This, as a principle, is purely God's work; as it is an act, or as it is exercised under the influence of divine grace, it is man's act: "that ye believe"; the object of it is Christ, as sent by the Father, as the Mediator between God and men, as appointed by him to be the Saviour and Redeemer; and believing in Christ, is believing in God that sent him. The Jews reduce all the six hundred and thirteen precepts of the law, for so many they say there are, to this one, "the just shall live by his faith", ( Habakkuk 2:4 ) . ^F5