The name Judah (Yehudah) comes from the Hebrew root y-d-h — to acknowledge, to confess, to praise. Jacob knows this, and Targum Pseudo-Jonathan will not let the wordplay pass unused. "Jehuda, thou didst make confession in the matter of Tamar: therefore shall thy brethren confess thee, and shall be called Jehudain from thy name" (Genesis 49:8).
The whole nation Israel will one day be called Yehudim — Jews — because of a confession. The specific confession was brutal. Tamar, Judah's daughter-in-law, was about to be burned for a pregnancy Judah himself had caused. She sent him his staff and seal and asked whose they were. Judah had one breath to decide. He said: "She is more righteous than I" (Genesis 38:26). He confessed in public. He saved her life and his own soul.
The Targum reads this moment as the origin of Judah's kingship. A royal line requires a king who can say I was wrong. David, Judah's descendant, would say it when Nathan confronted him (2 Samuel 12:13). The Messiah, the tradition teaches, will come from a house that learned early to bow its head. The tribe of confession became the tribe of the crown.