Paul suddenly stops the flow of his argument and asks a question: What, then, was the purpose of the law? (v. 19). This question reflects Paul's awareness that his argument so far would lead his readers to wonder whether he has denied any purpose to the law. If the inheritance of the promised blessing does not depend on the law, as Paul has just declared (v. 18), then why was the law given by God? Paul's answer is important for us as we wrestle with similar questions regarding the application of the Mosaic law. How should Christians relate to the Mosaic law today?

In this section Paul first asks his major, initial question regarding the purpose of the law and replies briefly (vv. 19-20), then asks a supplementary question regarding the relation of the law to the promise of God and supplies an explanation (vv. 21-22), and finally presents two images to illustrate more fully God's purpose for the law (vv. 23-25).