S. Motyer, “Paul, Theology Of” in The Evangelical Dictionary of Theology

Paul’s conversion took him from one “people of God” to another. The tension inevitably produced by these rival claims meant that he had to establish his theology of the church from first principles upward. The most important issue in the struggle was justification, because of the common conviction that God will one day judge the world (cf. Rom. 3:6). Who will then be acquitted, “justified”? Paul rejected his Jewish contemporaries’ view (which he had previously accepted) that God’s covenant with Israel assured it of forgiveness and acquittal. If this alone were necessary, why did Christ die (Gal. 2:21)? The bald fact of the death of God’s Son showed Paul that justification could not come through “works of the law” (Gal. 2:16; 3:10; Rom. 3:20)—i.e., through mere dependence, however heartfelt and zealous, on the status conferred by God’s gift of the law. Even the most impeccable Jewish record, such as Paul himself had (Gal. 1:14; Phil 3:4-7), was useless. Though prompted to this view by his sudden encounter with Christ, Paul yet came to see that the OT points to its own weakness, by offering nothing more secure than a precarious existence “under a curse” (Gal. 3:10), where human weakness might at any moment trigger the curses listed in Deut. 28:15-68. Christ alone could give assurance of justification, because Christ alone had overcome the sin which made the law incapable of giving the promised blessing (Rom. 7:7-8; 8:3). But this dethroning of the law as the central salvific principle demolished the barriers of Israel and opened justification to all who would simply embrace Christ and, through reception of his Holy Spirit, begin to evidence the faith and love for God for which the OT longed in vain (Deut. 6:4; 9:13-14; 29:4; Ezek. 18:31; 36:26; Rom. 5:5; 6:17; Gal. 3:14,23-26). Paul was thus able to claim that he, with his “law-free gospel” offered to all alike, was more faithful to the law (Rom 3:31) than were those who urged that salvation could be enjoyed only within the borders of Israel. Through Christ, who is its “end” (Rom. 10:4), the law is delivered from its bondage to sin (Rom. 7:10-11) and its nationalist limitations (Gal. 5:3) and restored to its proper role as the guide of the people of God. Hence Paul’s confident handling of the OT.