It is a work of grace on our behalf, but it is a work of grace because it is first of all a work of fulfilling the law. We are saved by works, the works of Jesus. Jesus the Messiah thus performs a double work of redemption. First, as the new Adam (the Son of the Man [Adam], a title Jesus uses extensively in the Synoptics), he acutalizes tre humanity in himself by perfectly fulfilling the moral law of the Old Testament. Second, in his death and resurrection he fulfills the ceremonial law of the Old Testament as the perfect substitute who bears the penalty of death on our behalf, satisfying, vindicating and propitiating divine oliness once for all. Jesus Christ is the centrla figure of history, redeeming by his righteous work all believers before him and all who come after him. Viewed in this way, OT believers too were saved by prevenient faith in Christ through the presence of the Spirit in their lives, but within boundary markers that were preparatory to the Messiah’s coming and therefore forward-leaning. Enoch, Noah and ABraham were justified by faith, as were the faithful in the period of the law that was in place till the death of Christ on the cross.
Added Emphasis. Royce Gordon Gruenler, “Atonement in the Synoptic Gospels and Acts,” The Glory of the Atonement (InterVarsity: Downers Grove, IL, 2004), 96.