Romans 3:19
Now we [all] know that everything the law says applies to those who are under [obligation to obey] that law, [Note: Here "the law" appears to refer to the Old Testament Scriptures generally, since Psalms and Isaiah are quoted. See verses 10-18]. This is so that the mouth of every objector may be stopped [i.e., from making excuses for his sin], and thereby bring the entire world under God's judgment [i.e., both Jews and Gentiles].
Romans 2:1
So, whoever you are, you people do not have any excuse for judging people [Note: At this point Paul begins addressing the Jews. See verse 17]. For in a matter where you judge someone else [to be wrong] you [actually] condemn yourselves, because you are practicing the same things [you condemn them for doing].
Romans 3:27
Where then is the [basis for] boasting [i.e., over being right with God]? There is not any. Is it by [obedience to] a law? Is it by doing certain deeds? Not at all, but by a law of faith.
Romans 5:1-2
So, since we are made right with God by [our] faith, we have peace with Him through our Lord Jesus Christ.
Romans 9:19-20
But you [i.e., probably an objecting Jew] will say to me, "Why does God still find fault [with people]? For who can [successfully] resist what God wants to do?"
1 Corinthians 4:7
For who makes you different [from each other]? [i.e., with some being viewed as superior and others inferior]. And what do you have that you did not receive [from God]? But if you received it [from Him], then why do you boast as though you did not [receive it as a gift]?
Ephesians 2:3-5
All of us [Jews] also once lived among such people, fulfilling the improper cravings of our physical being and doing what our bodies and minds desired. In this natural [unconverted] state we were deserving of [God's] wrath, just like the rest [of mankind].
Titus 3:3-7
For we [Christians] were also once foolish, disobedient, deceived, enslaved to various kinds of [evil] desires and [sinful] pleasures. [We used to] live in malice and envy, hating people and being hated by them.