'Because what may be known of God is manifest in them, for God has shown it to them............Who, knowing the righteous judgement of God that those who practise such things are worthy of death......... for when the Gentiles, who do not have the law, by nature do the things of the law, these, although not having the law, are a law to themselves, who show the work of the law written on their hearts, their conscience also bearing witness, and between themselves their thoughts accusing or else excusing them' (
Romans 1:19, 32; 2:14-15).
Your disregard for context detracts from the “he is a Jew who is one inwardly” motif that Paul has constructed in chapter 2 that leads into the question of Ro 3:1 and concludes in Ro 9:
If , because God is no respecter of persons, Jew and non-Jew alike are to be judged by their works with or without the law; – vv 5-13
And if non-Jews that don’t have the law can do by nature the things of the law because the law has been written in their hearts (synonymous with the circumcision of heart in v 29); vv 14-15
And if Jews that have the law and glory in it have through their transgression of it caused the name of God to be blasphemed among the non-Jews; vv 17-24
And if the Jews’ circumcision becomes uncircumcision if they transgress the law; v 25
And if non-Jews fulfill the law their uncircumcision becomes circumcision and they will judge the Jews; vv 26-27
And if Jews outwardly, circumcised in the flesh by the letter are not the real Jews; v 28
And if real Jews are those inwardly circumcised in heart in the spirit, not the letter; v 29
Then:
1
What advantage then hath the Jew? or what is the profit of circumcision?
Paul begins his answer here:
2 Much every way:
first of all, that they were intrusted with the oracles of God.
And comes back to it here:
3 For I could wish that I myself were anathema from Christ for my brethren`s sake,
my kinsmen according to the flesh:
4
who are Israelites; whose is the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises;
5
whose are the fathers, and of whom is Christ as concerning the flesh, who is over all, God blessed for ever. Amen. Ro 9
But:
6 But it is not as though the word of God hath come to nought. For
they are not all Israel, that are of Israel:
7 neither, because they are Abraham`s seed, are they all children: but, In Isaac shall thy seed be called.
8 That is,
it is not the children of the flesh that are children of God; but the children of the promise are reckoned for a seed. Ro 9
Reiterating the “he is a Jew who is one inwardly” motif of chapter 2.