Are those who are now under the new covenant, Christians, considered to be Israelites now? Are we the part of the nation of Israel? Figuratively speaking, of course.
Christians are not physically Israelites, but we are the spiritual equivalent.
"For he is not a Jew who is one outwardly, nor is circumcision that which is outward in the flesh; but he is a Jew who is one inwardly; and circumcision is that of the heart, in the Spirit, not in the letter; whose praise is not from men but from God" (Romans 2:28-29).
"But it is not that the word of God has taken no effect. For they are not all Israel who are of Israel, nor are they all children because they are the seed of Abraham; but, "In Isaac your seed shall be called." That is, those who are the children of the flesh, these are not the children of God; but the children of the promise are counted as the seed" (Romans 9:6-8).
"Therefore it is of faith that it might be according to grace, so that the promise might be sure to all the seed, not only to those who are of the law, but also to those who are of the faith of Abraham, who is the father of us all" (Romans 4:16).
"For you are all sons of God through faith in Christ Jesus. For as many of you as were baptized into Christ have put on Christ. There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female; for you are all one in Christ Jesus. And if you are Christ's, then you are Abraham's seed, and heirs according to the promise" (Galatians 3:27-29).