Musar sur Les Nombres 7:12

As soon as Israel left Egypt, the Psalmist tells us: בצאת ישראל ממצרים … היתה יהודה לקדשו, ישראל ממשלותיו. "When Israel went forth from Egypt,…. Yehudah became His holy one, Israel His dominion" (Psalms 114,1-2). Later in Numbers 10, 14, when the people were divided into four camps, Yehudah again was the first army to break camp and march ahead of the people. Yehudah was also the first of the twelve princes to offer his offering in honor of the dedication of the Holy Tabernacle (Numbers 7,12). This pre-eminence of the tribe of Yehudah also continued after the people inherited the land of Israel, until the days of Samuel, when the people demanded to be led by a king, and the choice fell on Saul from the tribe of Benjamin. As already explained, the position of king was only on loan to the tribe of Benjamin, as apparent from the very name שאול, "something borrowed." Within less than a generation, a scion of the tribe of Yehudah, David, became the king of Israel. Ever since, Jacob's blessing in Genesis 49, 10 that "the scepter of Royalty will not depart from members of the tribe of Yehudah" has been fulfilled.