The law could not save in or from sins, yet it gave the Jews advantages for obtaining salvation. Their stated ordinances, education in the knowledge of the true God and his service, and many favours shown to the children of Abraham, all were means of grace, and doubtless were made useful to the conversion of many. But especially the Scriptures were committed to them. Enjoyment of God's word and ordinances, is the chief happiness of a people. But God's promises are made only to believers; therefore the unbelief of some, or of many professors, cannot make this faithfulness of no effect. He will fulfil his promises to his people, and bring his threatened vengeance upon unbelievers. God's judging the world, should for ever silence all doubtings and reflections upon his justice. The wickedness and obstinate unbelief of the Jews, proved man's need of the righteousness of God by faith, and also his justice in punishing for sin. Let us do evil, that good may come, is oftener in the heart than in the mouth of sinners; for few thus justify themselves in their wicked ways. The believer knows that duty belongs to him, and events to God; and that he must not commit any sin, or speak one falsehood, upon the hope, or even assurance, that God may thereby glorify himself. If any speak and act thus, their condemnation is just.
Matthew Henry's Commentary on Romans 3:4
Commentary on Romans 3:1-8
(Read Romans 3:1-8)
The law could not save in or from sins, yet it gave the Jews advantages for obtaining salvation. Their stated ordinances, education in the knowledge of the true God and his service, and many favours shown to the children of Abraham, all were means of grace, and doubtless were made useful to the conversion of many. But especially the Scriptures were committed to them. Enjoyment of God's word and ordinances, is the chief happiness of a people. But God's promises are made only to believers; therefore the unbelief of some, or of many professors, cannot make this faithfulness of no effect. He will fulfil his promises to his people, and bring his threatened vengeance upon unbelievers. God's judging the world, should for ever silence all doubtings and reflections upon his justice. The wickedness and obstinate unbelief of the Jews, proved man's need of the righteousness of God by faith, and also his justice in punishing for sin. Let us do evil, that good may come, is oftener in the heart than in the mouth of sinners; for few thus justify themselves in their wicked ways. The believer knows that duty belongs to him, and events to God; and that he must not commit any sin, or speak one falsehood, upon the hope, or even assurance, that God may thereby glorify himself. If any speak and act thus, their condemnation is just.