Biblical Context:
The event of Joshua releasing the Eastern Tribes is recorded in the Book of Joshua, specifically in Joshua 22:1-9. This passage marks a significant moment in the history of the Israelites as they transition from conquest to settlement in the Promised Land. The Eastern Tribes—Reuben, Gad, and the half-tribe of Manasseh—had fulfilled their commitment to assist the other tribes in conquering Canaan and were now permitted to return to their allotted territories east of the Jordan River.

Historical Background:
The Eastern Tribes had initially requested to settle on the east side of the Jordan River because of the region's suitability for their large herds and flocks (Numbers 32). Moses granted their request on the condition that they would first help their fellow Israelites in the conquest of Canaan. This agreement was honored, and after years of military campaigns under Joshua's leadership, the land was largely subdued.

Scriptural Account:
In Joshua 22:1-9, Joshua commends the Eastern Tribes for their faithfulness and obedience to the commands of Moses and the LORD. He acknowledges their unwavering support and loyalty, stating, "You have not deserted your brothers these many days to this day, but have kept the charge of the commandment of the LORD your God" (Joshua 22:3). Joshua then blesses them and releases them to return to their homes with great wealth, including livestock, silver, gold, bronze, iron, and clothing, as a reward for their service (Joshua 22:8).

Theological Significance:
This event underscores the importance of unity and cooperation among the tribes of Israel. The Eastern Tribes' willingness to fight alongside their brethren exemplifies the covenantal relationship and mutual responsibility that bound the Israelites together. Their actions reflect a commitment to God's commands and the collective mission of the nation.

Furthermore, Joshua's blessing and release of the Eastern Tribes highlight the themes of faithfulness and reward. The tribes' obedience to God's command through Moses resulted in tangible blessings and a peaceful return to their families. This narrative reinforces the biblical principle that faithfulness to God and His commandments leads to divine favor and blessing.

Cultural and Social Implications:
The return of the Eastern Tribes to their lands east of the Jordan River also had social and cultural implications. It marked the beginning of a new phase in Israel's history, where the focus shifted from military conquest to settlement and community building. The tribes were now tasked with establishing their societies according to the laws and statutes given by God, ensuring that their communities reflected the covenantal values of justice, mercy, and worship.

Key Themes and Lessons:
1. Faithfulness and Obedience: The Eastern Tribes' adherence to their promise serves as a model of faithfulness and obedience to God's commands.
2. Unity and Cooperation: The event emphasizes the importance of unity among God's people, as they work together towards a common goal.
3. Divine Reward: The blessings bestowed upon the Eastern Tribes illustrate the principle that God rewards those who are faithful to His covenant.
4. Transition and New Beginnings: The release of the Eastern Tribes signifies a transition from conquest to settlement, highlighting the ongoing journey of God's people in fulfilling His promises.

Conclusion:
The release of the Eastern Tribes by Joshua is a pivotal moment in the biblical narrative, reflecting themes of faithfulness, unity, and divine blessing. It serves as a reminder of the importance of obedience to God's commands and the rewards that follow such faithfulness.