The Jews had great advantage with circumcision. They had God’s Word. Their faithlessness doesn’t nullify God’s faithfulness. The fact that our unrighteousness shows God’s righteousness doesn’t make God unrighteous to inflict wrath on us. If my sin (lie) causes God’s truth to abound to His glory he is still righteous to judge. Sinning so that good may come is not justified and that’s not what the Apostles taught. Jews aren’t any better off, they are still under sin. No one is righteous, all have fallen short of the glory of God. The law speaks to those under the law so the whole world is accountable to God. No one will be justified in God’s sight by human works. Through the law comes knowledge of sin. God’s righteousness has been manifested apart from the law – the righteousness of God through faith in Jesus Christ for all who believe. All have fallen short of the glory of God. The only way we can be justified before God is by His grace as a gift through redemption that is in Christ Jesus, who’s propitiation is received by faith. This showed God’s righteousness – passing over sin – that He is just and the justifier of the one who has faith in Jesus. Boasting is excluded by the law of faith. We hold that one is justified by faith apart from works of the law. God is the God of Jews and Gentiles – God is One – who will justify the circumcised by faith and the uncircumcised through faith. We uphold the law by faith.
There is no boasting in salvation because we didn’t earn it, and there is no boasting in salvation because we don’t deserve it. Praise God that He gives His people faith, and that when we have faith in the death and resurrection of Christ we are justified, and Jesus’ satisfying of the eternal wrath of God that we deserve has been applied to us. We have hope to be with God because of Christ. When you see your sin, don’t despair look to Christ.