How does Paul argue from entrusted words and sin to grace and faith?

Paul asks the advantage of being a Jew and the profit of circumcision. There is much advantage, first because God’s words were entrusted to them. Some people’s unbelief cannot make God’s faith void: God is true and every man a liar, as the written words about justification in speech and overcoming when judged declare. The annotation says God is essentially true while men in their own capacity are liable to lies and errors, yet God keeps his promise to preserve the church in all truth, citing John 16:13.

If human injustice commends God’s justice, is God unjust in executing wrath? Speaking according to man, Paul rejects this, asking how otherwise God judges the world. If God’s truth abounds through a lie to his glory, why is the liar judged a sinner? Paul rejects the slander that he and his companions teach doing evil so good may come, saying its condemnation is just. Jews and Greeks alike have been charged as under sin. He cites the absence of a just man; the annotation specifies justification through faith and grace rather than the virtue of nature’s or Moses’s law. The quotations describe none understanding or seeking God, all turning unprofitable, deceitful tongues, venomous lips, curses, bitterness, bloodshed, destruction, misery, ignorance of peace and absence of God’s fear.

The law speaks to those within it, stopping every mouth and subjecting the world to God. Works of the law justify no flesh; the law gives knowledge of sin. God’s justice without the law is now manifest, witnessed by law and prophets, through Jesus’s faith to all believing without distinction. All have sinned and need God’s glory, being justified freely by grace through redemption in Christ. God proposes him as propitiation through faith in his blood, showing justice in the remission of former sins through forbearance and in the present time, as just and the justifier of one having Jesus’s faith.

Boasting is excluded by the law of faith rather than works. A man is accounted justified by faith without works of the law. The annotation denies presumptuous assurance and describes firm, lively belief in revealed and promised things, working through charity and encompassing hope, love, repentance and sacraments. It distinguishes works of nature or Moses’s law preceding Christ’s faith from works following and proceeding from faith. God belongs also to the Gentiles: one God justifies circumcision by faith and uncircumcision through faith. Faith establishes rather than destroys the law.