In Genesis 48 Joseph brought his two sons, Ephraim and Manasseh to his father Israel for a blessing. What Israel did was adopt them by putting his name on the sons of Joseph. So from that time on, Ephraim and Manasseh were part of the children of Israel, making thirteen tribes in all. Also part of the blessing Israel gave to the sons of Joseph is that Manasseh would become a great nation and Ephraim would be a company of nations. Now we know all the names of the people that make up the tribes of Israel.
Lets find out who the Jewish people descended from.
The word Jew is used ten times in the Old Testament and each time the same Hebrew word is used. Lets take a look at the definition of Jew from the Strong's Concordance. In the New Testament the word Jew is used twenty two times and each time the same Greek word is used. Lets take a look at the definition of Jew from the Strong's Concordance. So we see that people that have Jewish blood in them are descended from Judah.