Definition:
Eternal Establishment refers to the divine promise and assurance of God's unchanging and everlasting covenant with His people, His kingdom, and His purposes. This concept is rooted in the biblical narrative, where God commits to establishing His kingdom and His people forever, often through covenants with key figures such as David and through the ultimate fulfillment in Jesus Christ.

Biblical Foundations:

1. Davidic Covenant:
The promise of eternal establishment is prominently featured in the covenant God made with King David. In 2 Samuel 7:12-16, God promises David that his throne will be established forever: "When your days are complete and you rest with your fathers, I will raise up after you your descendant, who will come from your own body, and I will establish his kingdom. He will build a house for My name, and I will establish the throne of his kingdom forever" (2 Samuel 7:12-13). This covenant is foundational for understanding the messianic hope and the eternal kingdom that God promises through David's lineage.

2. Messianic Fulfillment:
The New Testament identifies Jesus Christ as the fulfillment of the Davidic Covenant, establishing an eternal kingdom. In Luke 1:32-33, the angel Gabriel announces to Mary: "He will be great and will be called the Son of the Most High. The Lord God will give Him the throne of His father David, and He will reign over the house of Jacob forever. His kingdom will never end" . This passage underscores the belief that Jesus is the promised descendant of David, whose reign is eternal.

3. God's Unchanging Nature:
The concept of eternal establishment is also tied to the unchanging nature of God. In Psalm 102:25-27, the psalmist declares: "In the beginning You laid the foundations of the earth, and the heavens are the work of Your hands. They will perish, but You remain; they will all wear out like a garment. Like clothing You will change them, and they will be passed on. But You remain the same, and Your years will never end" . This passage highlights God's eternal nature, which undergirds His promises and covenants.

4. The Kingdom of God:
The eternal establishment is ultimately realized in the Kingdom of God, which is both a present reality and a future hope. Jesus' teachings often centered on the Kingdom of God, emphasizing its eternal nature. In Matthew 6:10, Jesus teaches His disciples to pray, "Your kingdom come, Your will be done, on earth as it is in heaven" . This prayer reflects the desire for God's eternal kingdom to be fully realized on earth.

5. Eternal Life for Believers:
The promise of eternal establishment extends to believers, who are assured of eternal life through faith in Jesus Christ. In John 3:16, it is written: "For God so loved the world that He gave His one and only Son, that everyone who believes in Him shall not perish but have eternal life" . This verse encapsulates the promise of eternal life, which is part of the broader theme of eternal establishment in God's redemptive plan.

Theological Implications:

Eternal Establishment is a testament to God's faithfulness and sovereignty. It reassures believers of the certainty of God's promises and the ultimate fulfillment of His divine plan. The concept underscores the continuity of God's work from the Old Testament covenants to the New Testament fulfillment in Christ, affirming the eternal nature of God's kingdom and His unchanging commitment to His people.