Formerly, they were not a people, henceforth they are the “people of God”
Because of this, the First Letter of Peter, addressed mostly to believers converted from paganism, confers on them the titles “chosen people” 120 and “holy nation” 121 in the same manner as those converted from Judaism. 122 The Second Letter of John calls the Christian community whom he addresses as “the chosen lady” (v.1), and “your chosen sister” (v.13) the community from which it was sent. (1 Th 1:4). Thus, the conviction of partaking in the divine election was communicated to all Christians.
36. In the Letter to the Romans, Paul makes clear that for Christians who have come from paganism, what is involved is a participation in Israel’s election, God’s special people. The Gentiles are “the wild olive shoot”, “grafted to the real olive” to “share the riches of the root” (Rm ,24). They have no need to boast to the prejudice of the branches. “It is not you that support the root, but the root that supports you” ().
To the question of whether the election of Israel remains valid, Paul gives two different answers: the first says that the branches have been cut off because of their refusal to believe (,20), but “a remnant remains, chosen by grace” (11:5). It cannot, therefore, be said that God has rejected his people (11:1-2). “Israel failed to attain what it was seeking. The elect [that is, the chosen remnant] attained it, but the rest were hardened” (11:7). The Jews do not cease to be called to live by faith in the intimacy of God “for the gifts and calling of God are irrevocable” ().
The second response says that the Jews who became “enemies as regards the Gospel” remain “beloved as regards election, for the sake of the ancestors” () and Paul foresees that they will obtain mercy (,31)
The New Testament never says that Israel has been rejected.