The Apostle Paul defined what it means to be a "Jew" in Romans chapter 2. **Romans 2:28-29 (NKJV) **- "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."

That's who a "Jew" is under the New Covenant - the Covenant of Jesus Christ. In fact Paul goes even further in Galatians. Galatians 3:28 (NKJV) - "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."