Balaam tries to curse Israel but the Lord turns the curse to blessing. He alludes to the exodus of Jacob and Israel from Egypt, and then says, “He couches, he lies down as a lion, and as a lion, who dares rouse him? Blessed is everyone who blesses you, and cursed is everyone who curses you” (Numbers 24:9).
This is not simply a blessing, but a very specific blessing. On his deathbed, Jacob blessed his sons, and to Judah said: “Judah is a lion’s whelp; from the prey, my son, you have gone up. He couches, he lies down as a lion, and as a lion, who dares rouse him up?” (Genesis 49:9).
Balaam, in short, applies the blessing of Judah to all Israel. Israel is conceived as receiving the blessing on the tribe of Judah. They are all counted as Judahites - as “Jews.”
Balaam is the inventor of the concept of “Jew.”