The Tribe of Judah was one of the largest and most populous of the twelve tribes of Israel, named after and descending from the Patriarch Judah, the son of Jacob. Arguably Judah was the most influential of all the tribes, being the location of Jerusalem- the capital city of Israel and location of God's Temple and seat of the royal throne. All of David's ancestors and descendants, including most of the Kings of Israel were from this tribe; consequently Jesus Christ was as well. Later in it's history, The Tribe of Judah separated from the rest of Israel, along with the Tribe of Benjamin (and would later be joined by the half tribes of Manasseh and Ephraim) to form the Nation of Judah.
Like all the tribes of Israel, the tribe of Judah began as the immediate family of Judah, over time enlarging to multiple family units before branching out further into much larger and genealogically dispersed groups.
While no clear reason is given, even Jacob’s blessing of Judah foretold Judah’s prominent and influential role in Israel’s future. Jacob’s blessing for Judah called him a lion who would dominate his brother’s descendants . This serves as a foreshadowing to Judah’s key military roles in the days of conquest, judges and beyond. The Tribe of Judah would never lose its ruling power- a “scepter”- they would command not only other Israelites, but would have influence over other people groups. Lastly, Jacob foretells that Judah will have great prosperity through the fruits of their land and the success of its inhabitants .
The Emerging Tribe
During the 400 years in Egypt, Judah’s family grew from a large family to an entire tribe. After the exodus, Judah was led by Nahson the son of Amminadab who executed the will of God and the leadership of Moses in his tribe. Israel’s first census for determining the amount of war-eligible men (20 years or older) determined that Judah had 74,600 eligible warriors- the largest of any of the tribes of Israel. This number did not include any other Judahites so the number would have been much larger.
In the Wilderness
For Israel's camp surrounding the Tabernacle, Judah was chosen to be the leading tribe of the eastern group (consisting also of Issachar and Zebulun). When the camp of Israel departed Sinai, Judah's tribe marched first and lead the way for the rest of the nation .
When scouts were sent into the Promised Land of Canaan, Caleb son of Jephunneh went on behalf of Judah. Out of all the scouts, only Caleb believed Israel would be able to conquer the land from the giant Anakites under the protection of Yahweh.
After a second census of the generations after The Exodus, the Tribe of Judah counted 76,500- nearly a 2,000 increase in war-eligible men in their tribe (not counting women, children and men not eligible for military service).
While still in the wilderness, Caleb was chosen as the leader responsible for ensuring proper allocation of Judah's land once it was conquered .
In a symbolic depiction of God's covenant with Israel, the Tribe of Judah stood atop Mount Gerizim alongside the Tribe of Simeon, Tribe of Levi, Tribe of Issachar, the House of Joseph and the Tribe of Benjamin to declare God's blessings to the nation. Standing opposite them on Mount Ebal was the other tribes who pronounced God's curses.
Moses Blesses the Tribes
Before Moses passed away, he gave a blessing to each of the tribes akin to the one Jacob gave to the tribes' forefathers. For Judah he prayed that God would hear them, protect them and fight for them in their future battles .
Conquest & Allotment of the Land
Achan is Discovered
Achan, a Judahite and member of the Zerahite clan took dedicated (herem) loot from Jericho, thus Israel was defeated in battle near Ai. In an effort to uncover the violator of the sacred devotion of war plunder to Yahweh, Joshua summoned all the tribes of Israel. Through a painstaking process, Joshua discerned that a member of Judah had committed the crime via casting lots. Then casting further lots, the clan of Zerah was discerned and following this each man was evaluated against the lottery until Zabdi's family was discerned. Finally, Zabdi's son Achan was discerned. 
After the conquest of many Canaanite cities, Caleb desired the land he was owed. Traveling with one of their beloved tribal heroes, Judah camped at Gilgal where Joshua was present. While camped at Gilgal, Caleb formally asked Joshua for the inheritance he was obligated.
At this point in the text, the allotment of the land of Judah is given in detail in relation to the specific inheritance of Caleb. The allotment dictated what rightfully belonged to Judah, but not necessarily what they currently possessed. Also, the insertion of Judah's territorial belongings may not be implying that the historical event of assigning land to Judah happened at the same time. [The actual event of allotment happened either under Moses or Joshua, precise determination is needed by future editor]
Simeon and Judah's Alliance
After the death of Joshua, many parts of the Promised Land remained to be conquered. Judah still had many cities to capture that it had been allotted. Being prompted by God's assurance of victory, Judah continued to press forward their campaign for the lands that belonged to them. The Tribe of Judah decided to ask the Tribe of Simeon for their aide in conquering the areas that they were entitled to, in exchange for offering their own support for Simeon. As each tribe was responsible for conquering their own territory, this was a mutually beneficial agreement between Judah and Simeon.
Defeat of Bezek
At the area of Bezek, Judah and Simeon defeated around 10,000 Canaanite and Perizzite enemies led by Adoni-Bezek. Adonibezek fled but was captured As a way to shame and humiliate him, Judah removed Adonibezek's thumbs and big toes- Adonibezek recognized this as divine retribution from God (Elohim). 
Jerusalem, Hebron and Debir
Judah also attacked the city of Jerusalem, killing many inhabitants and burning the city down. Later, Judah captured small Canaanite settlements and villages in the hill-country of the Negev and in the lowlands.
Judah went on to attack Hebron, at the time known as Kiriath-Arba. Caleb had been permitted this town for his own personal inheritance, therefore he led the attack. In the attack three Anakites: Sheshai, Ahiman and Talmai were defeated.
From there Judah went up against the city of Debir, known as Kiriath-Sepher at the time. Caleb offered his daughter Achsah in marriage to the brave warrior who would lead the charge and capture the city on his behalf. Othniel, a future judge of Israel, led the attack and became Caleb's son-in-law.
Settling Conquered Territory
As Judah conquered territories in their allotment, they began to settle in these towns. A clan of Midianites descending from Reuel known as the Kenites moved from their community near the ruins of Jericho and settled in the towns of Judah.
Having completed their end of the bargain, Judah now owed Simeon their help with conquering their territory. In the process of many battles alongside Simeon, Judah captured Hormah on behalf of Simeon. In addition they defeated the Philistine cities of Gaza, Ashkelon and Ekron. The text of Judges emphasizes the role of Judah in these battles and the promise God made to Judah for victory in their battles. However, Judah and Simeon were unable to defeat the people of the plain who had iron chariots. 
Before a King
After the incident involving the Levite and his concubine in Gibeah, Benjamin, Israel declared war with the Tribe of Benjamin. As they prepared for Battle against Gibeah at Bethel, God commanded Judah to lead the attack force.
During the age of the judges, Ammon attacked Judah as well as Ephraim and Benjamin.
Judah experienced the oppression of foreign nations again as a result of Israel's evil behaviors. Seeking after Samson, the Philistines assembled in Judah and attacked Lehi. When Judah asked Philistia why they were encroaching on their lands they explained that were occupying Judah, wishing to capture Samson. Judah sent a detachment 3,000 men to capture Samson at the cliffs at Etam and turn him in to the Philistines. After Samson reluctantly agreed to surrender to avoid bloodshed, Judah delivered Samson to occupied Lehi. 
Tribe of David
David's Asylum in Judah
During the reign of King Saul, a young shepherd boy descended from Boaz named David rose to prominence within the kingdom of Israel. Hailing from the small town of Bethlehem, David became both a national and tribal hero.
When Saul became jealous of David’s popularity and military successes, he vowed to kill him. As David went on the run, he traveled to a fortress known as Mizpah in Moab. Leaving his father and mother under the protection of Moab’s King, the prophet Gad advised David to seek asylum in his home, Judah. Therefore, David went and hid in a forest of Judah known as Hereth. 
Hiding with David in the Hereth Forrest was a militia of men loyal to him. While hiding here, David got word of an attack on the Judahite citadel, Keliah by the Philistines. He received God’s blessing to go and intervene against the Philistines- however, David’s men were afraid. Having great fear of Saul’s armies in Tribe of Judah, how much more afraid they would be fighting the Philistines. 
Hearing David was at Keliah, Saul's army surrounded the city. Threatening the townspeople and testing the loyalty of Judah in exchange for David, David fled the town before Saul could capture him. After David’s army intervened at Keilah, Saul vowed to find David in Judah, even if that meant shoving thousands of people out of his way.
From Keliah David went through Maon in the Arabah wilderness. Traveling to Engedi, the forces of David and Saul had a close encounter in some rocky hills. David and his men traversed the hills before Saul could capture them, thus earning the name of Moan- the Rock of Escape (or Divisions).
David continued asylum in Judah for some time. During this time he made alliances with the following cities and people groups: Bethel, Jattirm, Siphmoth, Racal, Horman, Athach, Hebron and the Kenites and the Jerahmeelites. . While hiding from Saul, David and his men literally "set foot" in or near the territories of these cities and protectorates of Judah. As in the case of Keliah, David may have given these both physical security and emotional safety from enemies such as the Philistines, Amalekites and even the whims of Saul's forces.
Philistine and Amalekite Concerns
Some time later, David lead military campaigns in order to receive the protection of the Philistines. As a reward, the Philistine King Achish gave Ziklag to David. Therefore, Ziklag became a city in Judah and was passed down to each of the kings of the future nation of Judah. The text also notes that David made raids in the Judah portion of the Negev.
During the reign of Saul, Amalek made raids against the Judah portion of the Negev and burned Ziklag. Finding an abandoned Egyptian who was a servant to an Amalekite. From this man, they received news that Amalek had made attacks in Judah. While the Amalekites were celebrating the spoil they had taken from Judah, David drove them out of Judah and recovered everything they had taken.
Judah's Loyalty to David
David decided to return the spoil taken by Amalek back to Judah. He sent the spoils to elders in all the cities of Judah that had been his allies during his asylum.
These relationships with the leaders of Judah would prove important to David in the future as he made a claim to the throne. David’s time seeking refuge in Judah and his protection of the land solidified their loyalty to him and not to Saul.
David, King of Judah- not Israel
David remained Ziklag two days following the death of Saul. Then he inquired of Yahweh if he should go any other city in Judah. And God instructed David to go to Hebron. Since Saul had died, David stepped forward to claim the throne that he had been promised by God through Samuel years ago. While the rest of Israel recognized the firstborn of Saul, Ishbosheth as King, Judah crowned David as their own king. Hebron became the capital of the Judahite monarchy for six and a half years, until Ishbosheth died. Then all of Israel recognized the rule of David and adopted him as king at Hebron.
- ↑ Gen 49:8-9 (Link)
- ↑ Gen 49:11-12 (Link)
- ↑ Exo 1:2 (Link)
- ↑ Num 1:27 (Link)
- ↑ Num 2:3 (Link)
- ↑ Num 10:14 (Link)
- ↑ Num 26:25 (Link)
- ↑ Num 34:19 (Link)
- ↑ Deut 33:7 (Link)
- ↑ Josh 7:16-21 (Link)
- ↑ Josh 14:6 (Link)
- ↑ Jdg 1:4-7 (Link)
- ↑ Jdg 1:10, Josh 15:13-14 (Link)
- ↑ Jdg 1:16 (Link)
- ↑ Jdg 1:17-21 (Link)
- ↑ Jdg 20:18 (Link)
- ↑ Jdg 15:9-13 (Link)
- ↑ 1 Sam 26:3-5 (Link)
- ↑ 1 Sam 23 (Link)
- ↑ 1 Sam 30:26-31 (Link)