They said therefore to him, "What must we do, that we may work the works of God?"
This is the work of God, that ye believe on him whom he hath sent ...  In all the New Testament, there is not a more instructive verse than this which designates faith in the Lord Jesus Christ as a work performed by men, but also in the ultimate sense a work of God. This statement demolishes the prevalent Protestant heresy that "There is nothing you can do to be saved!" Faith itself is something that must be done; but its importance is sufficient to justify its standing here as a synecdoche of all that must be done.  For more on synecdoche, see the index of my Commentary on Romans. As Dorris noted: "This verse illustrates the truth that the works of God are works ordained by God to be performed by men."[12]  For identification of seven Scriptural classifications of works, see my Commentary on Romans, p. 62.