The term “Jew” comes from the word “Judah,” in Hebrew it is actually the same word. First given to one belonging to the tribe of Judah or to the separate kingdom of Judah (2 Kings 16:6; 25:25; Jer. 32:12; 38:19; 40:11; 41:3), in contradistinction from those belonging to the kingdom of the ten tribes, who were called Israelites. The name “Jew” is primarily tribal (from Judah). It is first found in 2 Kings 16:6, as distinct from Israel, of the northern kingdom. The usage of the word "Jew" in the Bible seems to have been applied after the captivity from Babylon, Israelites were called Jews to distinguish their ethnicity from Gentiles. During the Captivity, and after the Restoration, the name, was extended to all the Hebrew nation without distinction (Esther 3:6, 10; Dan. 3:8, 12; Ezra 4:12; 5:1, 5). Originally this people were called Hebrews (Gen. 39:14; 40:15; Ex. 2:7; 3: 18; 5:3; 1 Sam. 4:6, 9, etc.), but after the Exile this name fell into disuse.

The "original Jews" are the physical descendents of Abraham, his son Isaac, and his son Jacob, it is through Jacob's sons they became the 12 tribes of Israel.   By New Testament times, the terms “Hebrew,” “Israelite,” and “Jew” had become synonymous. Paul called himself a Hebrew (2 Cor. 11:22; Phil. 3:5).

In the book of Esther the word Jew is used to make a distinction of the Israelites among those in captivity. During the Captivity, and after the Restoration, this name was extended to the whole nation (Esther 3:6, 10; Dan. 3:8, 12; Ezra 4:12; 5:1, 5). Originally this people were called Hebrews (Gen. 39:14; 40:15; Ex. 2:7; 3: 18; 5:3; 1 Sam. 4:6, 9, etc.), but after the Exile this name fell into disuse, in the New Testament we find Paul was known as a Hebrew (2 Cor. 11:22; Phil. 3:5). Hebrew, Jew, Israelite all are the same people.

One of the purposes of the Law was to keep the Jews (the nation of Israel) a distinct people from all others (Lev. 11:44-45; Duet. 14:1-2). The dietary and the clothing laws, their worship habits (Lev. I-7, 16, 23), their eating habits (Lev. 11:1-47), ' sexual habits (Lev. 12), their clothing habits (Lev. 19:19), and even the way they cut ' beards (Lev. 19:27; Exod. 19:5-8; 31:13).

The term “Hebrew” originated with Eber (great-grandson of Shem, who was the son of Noah), and through most of biblical history the term was used only when Jews identified themselves to Gentiles, as did Jonah (1:9),

Hebrew means crossed over from the other side. The first time we see this mentioned is with Abram

Gen 14:13 Then one who had escaped came and told Abram the Hebrew, for he dwelt by the terebinth trees of Mamre the Amorite.

The word is from the Hebrew yehudhi, originally meaning a member of the Hebrew tribe of Judah, the ancient territory of which was organized as the Roman province of Judaea in AD 6.

The term “Hebrew” originated with Eber (who was the great-grandson of Shem, the son of Noah). By New Testament times, the terms “Hebrew,” “Israelite,” and “Jew” had become interchangeable.

Two tribes sprang from Eber - Peleg and Joktan, Eber's eldest son received the name of Peleg, because in his days the earth, i.e., the population of the earth, was divided, in consequence of the building of the tower of Babel (Gen. 11:8).

To be a Jews one must be a physical descendents of Abraham, Isaac, and Jacob (as came12 tribes of Israel).  Many are descendents of one of those 12 tribes, Judah, from which they get their name "Jews."  The name “Jew” is basically tribal (from Judah). It is first found in 2 Kings 16:6, as distinct from Israel, of the northern kingdom.

The word Jew is found in John’s gospel the book of Acts and Paul’s writings Gal. 2:15, distinguishes Christians of “Jewish” race; distinguishes Jews from Samaritans, in John 4:9; from proselytes, in Acts 2:10. To Judaize to conform to Old Testament Jewish religious practices in the law Gal. 2:14. Hellenistic Jews were those who adopted the Greek language and certain Greek practices. The English word Jew is derived from the Latin Judaeus, meaning an inhabitant of Judea.

Paul explains since the New covenant that a Jew cannot boast of their keeping the law since they too are guilty of it. Rom 2:28-29 “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.”

Rom. 9:6-8 ... “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.” Paul explains the difference of the believer in new covenant. Gal 3:28-29 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.” Notice they are Abraham’s seed, not Jacob’s seed which is exclusively applied to Israel, the 12 tribes; who are Jews.

Deut. 7:6-7 "For you are a holy people to the LORD your God; the LORD your God has chosen you to be a people for Himself, a special treasure above all the peoples on the face of the earth. "The LORD did not set His love on you nor choose you because you were more in number than any other people, for you were the least of all peoples." God chose them and made them to be HIS “special people unto himself, above, the “apple of His eye” (Deut. 32:10; Lam. 2:18; Zech. 2:8).

So what of Israel today? “Has God cast away HIS people (natural Jews)? GOD FORBID... God hath not cast away HIS people which He foreknew..." (Romans 11:1, 2). The answer is NO! If they were cast away there would be no covenant the gentiles could be grafted into (Jer.31:31)