Christ's reply really solves the great problem which had long perplexed the schools of Palestine, and often, and even to the present hour, is dividing into two hostile camps the Christian Church. Jesus answered and said to them, This is the work of God.
Observe, not "works," but "work"—the one work which is the germ and the consummation of all the partial workings which are often made substitutes for it. There is "one work" which God would have man do.
Jesus admits that there is something to do ( ποιεῖν)—there is a labour, an effort of the will needed to do what God requires; and this is evident enough as soon as this great work is described, viz.
That ye believe on him whom he (the Father) sent; or, hath sent. ἵνα πιστεύητε,£ here preferred by the R.T. to πιστεύσητε (see John 13:19), marks the simple fact and continuous act of believing with the effort tending to such result; while the aorist would have pointed to one definite act of faith (see Westcott)..
To "believe on him," to habitually entrust one's self to the power and grace of Christ, to make a full moral surrender of the soul to the Lord, includes in itself all other work, and is in itself the great work of God.
"It is the Christian answer to the Jewish question" (Thoma). "Faith is the life of works, works the necessity of faith" (Westcott). "Faith is the highest kind of work, for by it man gives himself to God, and a free being can do nothing greater than give himself: St.
James opposes work to a faith which would be nothing but intellectual belief. St. Paul opposes faith, active faith, to works of mere observance. The 'faith' of St. Paul is really the 'work' of St. James, according to this sovereign formula of Jesus, 'This is the work of God, that ye believe'" (Godet).
Luther says, "To depend on God's Word, so that the heart is not terrified by sin and death, but trusts and believes in God, is a much severer and more difficult thing than the Carthusians or all orders of monks demand."
Schleiermachcr says, "This is the most significant declaration, that all eternal life proceeds from nothing else than faith in Christ."