Jacob compares Judah to a lion's cub, and Targum Pseudo-Jonathan explains exactly why. Two moments made Judah roar. "From the killing of Joseph my son thou didst uplift thy soul, and from the judgment of Tamar thou wast free" (Genesis 49:9).
The first moment was the pit at Dothan. His brothers wanted Joseph dead. Judah stood up and said, "What profit is it if we slay our brother and conceal his blood?" (Genesis 37:26). He traded Joseph's life for a sale to Ishmaelite traders. It was not a clean rescue — Joseph still went down to Egypt as a slave — but the young lion had lifted his voice, and a brother lived.
The second was Tamar. When she was dragged out to be burned, Judah could have stayed silent. He roared instead. "She is more righteous than I."
The Targum's point is striking. A lion is not only an animal of attack. A lion is an animal of rescue — of standing between the vulnerable and the blade. Judah earned the royal symbol not by killing but by saving. "He dwelleth quietly and in strength, as a lion; and as an old lion when he reposeth, who may stir him up?" The house of kings in Israel begins here.