Romans 9:23-24 "that He might make known the riches of His glory on the vessels of mercy, which He had prepared beforehand for glory,
(24) even us whom He called, not of the Jews only, but also of the Gentiles?"
Lets look at the definitions for Jew and Gentile from Strong's.
Here is the definition for Jew:
2453. Ioudaios, ee-oo-dah'-yos; from G2448 (in the sense of G2455 as a country); Judaean, i.e. belonging to Jehudah.
And now the definition for Gentile:
1484. ethnos, eth'-nos; prob. from G1486; a race (as of the same habit), i.e. a tribe; spec. a foreign (non-Jewish) one (usually by impl. pagan).
So we could rewrite the verse using more precise words from the definitions. For Jew we could use Judaean or Judahite. Judaean meaning someone who lives in Judea, but Paul was not talking about anyone who lived in Judea. In this case Judahite is the correct word. For Gentile we could write race, but because of how things are today I think that would be misunderstood.
The word gentile is a Latin word that was used instead of translating ethnos to an English word. The Greeks did not view the word ethnos or race as we do. To them it was tied more closely to how we understand the word nation. To the Greeks the root people of Ireland and Scotland would be of two different races or as we would say nations. This is true for they are different nations of what we consider the same race. So when the Greeks talked about other ethnos' in our words they meant different nations of the same race or kin. This is how Paul meant it as well as that is how he was trained. Here is the verse as written in the CNT.
Romans 9:23-24 "and so that He will make known the wealth of His honor upon vessels of mercy, which He previously prepared for honor;
(24) whom also He has called, us not only from among the Judaeans, but also from out of the Nations?"
So now we should look at who "the vessels of mercy, which He had prepared beforehand for glory" are and which Judaeans and Nations Paul is referring to. Paul tells us in the next two verses by telling us to go back to the book of Hosea to read all about it.
Romans 9:25 As He says also in Hosea: "I will call them My people, who were not My people, And her beloved, who was not beloved."
26 "And it shall come to pass in the place where it was said to them, 'You are not My people,' There they shall be called sons of the living God."
Hosea was called by Yahweh to preach to Israel. In that preaching through the naming of a child Yahweh, God, called the Israelites of the ten tribes by a new name, "not My people" in Hosea 1:9. However, that is not the end of the story. In verse 10 those people now called "not My people" are prophesied to be called, "sons of the living God". Who are "sons of the living God" today?
Matthew 5:9 "Blessed are the peacemakers, For they shall be called sons of God."
Luke 20:35 "But those who are counted worthy...are sons of God, being sons of the resurrection."
Romans 8:14 "For as many as are led by the Spirit of God, these are sons of God."
Galatians 3:26 "For you are all sons of God through faith in Christ Jesus."
27 "For as many of you as were immersed into Christ have put on Christ."
It should be obvious that through the promise of God those Israelites of the house of Israel, who were divorced, sent away and later escaped to Europe, Greece and other places, have become sons of the living God, or Christians, in great numbers.