Early Evidence of His Leadership. Jacob’s prophetic blessing had assigned a leading role to Judah (Ge 49:8; compare 1Ch 5:2), and its fulfillment is confirmed even by the early history of the tribe. Under the leadership of its chieftain Nahshon, Judah led the march through the wilderness. (Nu 2:3-9; 10:12-14) Also, this tribe produced Caleb, one of the two faithful spies who were privileged to reenter the Promised Land. Though advanced in years, Caleb had an active share in conquering the land allotted to Judah. The tribe itself was divinely designated to take the lead in the fight against the Canaanites, and it did so in association with the Simeonites. (Nu 13:6, 30; 14:6-10, 38; Jos 14:6-14; 15:13-20; Jg 1:1-20; compare De 33:7.) Later, Judah, again on the basis of divine authorization, led the punitive military action against Benjamin.​—Jg 20:18.

Fulfillment of Jacob’s Blessing in David. Finally God’s due time came for the transfer of royal power from the tribe of Benjamin to the tribe of Judah. At Hebron, after Saul’s death, the men of Judah anointed David as king. But the other tribes stuck with the house of Saul and made his son Ish-bosheth king over them. Repeated clashes occurred between these two kingdoms until the strongest supporter of Ish-bosheth, Abner, defected to David. Not long thereafter Ish-bosheth was murdered.​—2Sa 2:1-4, 8, 9; 3:1–4:12.

When David subsequently gained the kingship over all Israel, the ‘sons of Jacob,’ that is, all the tribes of Israel, lauded Judah and prostrated themselves to his representative as ruler. Therefore, David was also able to move against Jerusalem though it was basically in Benjamite territory and, after capturing the stronghold of Zion, to make it his capital. For the most part David conducted himself in a commendable way. So through him, the tribe of Judah was lauded for such qualities as justice and righteousness, and also for its services to the nation, including the maintenance of national security, as Jacob had foretold in his deathbed blessing. The hand of Judah was truly on the back of his enemies as David subdued the Philistines (who had twice sought to overthrow him as king in Zion), as well as the Moabites, Syrians, Edomites, Amalekites, and Ammonites. Thus, under David, Israel’s boundaries were at last extended to their God-ordained limits.​—Ge 49:8-12; 2Sa 5:1-10, 17-25; 8:1-15; 12:29-31.

By reason of the everlasting covenant for a Kingdom made with David, the tribe of Judah possessed the scepter and the commander’s staff for 470 years. (Ge 49:10; 2Sa 7:16) But only during the reigns of David and Solomon was there a united kingdom, with all the tribes of Israel prostrating themselves before Judah.