3:20 through the law comes knowledge of sin. See “The Three Purposes of the Law” at Deut. 13:10. While the Jews appeal to their possession of the law as proof of their privileged position before God, Paul has now demonstrated that any Jew’s sin is unveiled and condemned, not hidden and condoned, by the law (note Paul’s self-description in 7:7–11). At the Last Judgment, all argument with a perfectly just and omniscient Judge will be futile.