The first time we find the term Jews is when we read in II Kings of the Israelites and Syrians attacking them.
David’s grandson Rehoboam faced the breakup of the united twelve tribes. Judah and the much smaller tribe of Benjamin stayed with him and they formed the kingdom of Judah. The other ten tribes made Jeroboam their king and formed the kingdom of Israel.
They remained as two separate kingdoms for over two hundred years and sometimes they were at war with each other. The Bible lists the names and deeds of the kings of these different kingdoms and some prophets were sent to one and some to the other. Israel ended with the siege of Samaria and the deportation of its people by their Assyrian conquerors in 722 BC.
In 486 BC the Babylonians did the same to the people of Judah. But about fifty thousand of them returned to rebuild Jerusalem and Judah seventy years later as Jeremiah had prophesied.
It was only the people of Judah who were known as Jews. Technically they were also children of the father of all twelve tribes, Jacob who was renamed Israel. So they were also Israelites but the people of the northern kingdom of Israel could never be called Jews.
Name and etymology — WikipediaMain article: Jew (word)
The English word Jew continues Middle English Gyw, Iewe, a loan from Old French giu, earlier juieu, ultimately from LatinIudaeum. The Latin Iudaeus simply means Judaean, “from the land of Judaea“. The Latin term itself, like the corresponding GreekἸουδαῖος, is a loan from Aramaic Y’hūdāi, corresponding to Hebrew: יְהוּדִי, Yehudi (sg.); יְהוּדִים, Yehudim (pl.), in origin the term for a member of the tribe of Judah or the people of the kingdom of Judah. The name of both the tribe and kingdom derive from Judah, the fourth son of Jacob.
Now that the returning Jews or Judaeans have called their state Israel, the confusion is compounded. A new tradition calls all Israelites Jews and even makes Abraham, the great grandfather of the twelve tribes a Jew too. Now when was Abraham ever a Judaean?
Where are these ten tribes? Some of them moved down to Judah when the nation split up, to be near the Temple or to escape the heathen practices of Jeroboam but they were a minority and because they lived in Judah they too became Judaeans.
Josephus who lived in the first century AD wrote in The Antiquities of the Jews that two tribes were in the Roman empire but the ten tribes had become a vast number and were beyond the Euphrates and therefore outside of the Roman empire.
There are many prophetic references to the ten tribes in the Bible. The dry bones in Ezekiel were “the whole house of Israel” and not just the Jews. James wrote to ” the twelve tribes in the dispersion”. If they were a multitude when Josephus lived, how significant a people or peoples must they be now? Jacob’s last words at the end of Genesis were about what would happen to his sons’ descendants “in the last days”. Israel and Judah were to be reunited under a descendant of David.