In a "nut shell", Hebrew identifies with Nationality. Jew identifies with the religion.
This is not the case in the New Testament.
Matthew 27:37, "Above his head they placed the written charge against him: this is Jesus, the king of the Jews". Clearly not the king of the religion!
John 3:1, "Now there was a Pharisee, a man named Nicodemus who was a member of
the Jewish ruling council"
John 4:9, "The Samaritan woman said to him, “
You are a Jew and I am a Samaritan woman. How can you ask me for a drink?” (For Jews do not associate with Samaritans.)" Clearly, nationality.
Romans 1:16, "For I am not ashamed of the gospel, because it is the power of God that brings salvation to everyone who believes:
first to the Jew, then to the Gentile"
Romans 3:9, "What shall we conclude then? Do we have any advantage? Not at all! For we have already made the charge that Jews and Gentiles alike are all under the power of sin." (Jew and Gentile: different ethnicities)
Romans 10:12, "
For there is no difference between Jew and Gentile—the same Lord is Lord of all and richly blesses all who call on him"
1 Corinthians 1:22, "Jews demand signs and Greeks look for wisdom" (Jew and Greek: different ethnicities)
1 Corinthians 12:13, "For we were all baptized by one Spirit so as to form one body—
whether Jews or Gentiles, slave or free—and we were all given the one Spirit to drink." Ethnicity and social standing.
There are many more examples, but clearly the Jews are a distinct
people, different from Gentiles, Samaritans, Greeks, etc.