The "Key of David" is a symbolic term found in the Bible, representing authority and control, particularly in the context of access to the kingdom of God. This symbol is primarily mentioned in two significant passages: Isaiah 22:22 and Revelation 3:7.

Isaiah 22:22
In the Old Testament, the "Key of David" is first referenced in Isaiah 22:22, where it is associated with Eliakim, the son of Hilkiah. The verse states: "I will place on his shoulder the key to the house of David; what he opens no one can shut, and what he shuts no one can open." . Here, the key symbolizes the authority given to Eliakim over the house of David, indicating his role as a steward or governor with the power to grant or deny access to the royal household. This passage highlights the concept of divinely appointed authority, as Eliakim is chosen by God to replace Shebna, who had been unfaithful in his duties.

Revelation 3:7
The New Testament reference to the "Key of David" is found in Revelation 3:7, in the letter to the church in Philadelphia. The verse reads: "To the angel of the church in Philadelphia write: These are the words of the One who is holy and true, who holds the key of David. What He opens, no one will shut; and what He shuts, no one will open." . In this context, the "Key of David" is attributed to Jesus Christ, emphasizing His sovereign authority over the kingdom of God. Christ's possession of the key signifies His power to open and close doors, granting or denying entry into the eternal kingdom. This authority is rooted in His divine nature and His fulfillment of the Davidic covenant as the promised Messiah.

Theological Significance
The "Key of David" serves as a powerful symbol of Christ's ultimate authority and His role as the mediator between God and humanity. It underscores the belief that access to salvation and the blessings of God's kingdom are determined by Christ alone. The imagery of opening and shutting doors conveys the idea of divine judgment and grace, where Christ exercises His authority to welcome believers into eternal life or to exclude those who reject Him.

Historical and Cultural Context
In ancient Near Eastern cultures, keys were significant symbols of authority and trust. They were often large and carried on the shoulder, as mentioned in Isaiah, signifying the weight of responsibility. The key's association with the house of David reflects the Davidic covenant, where God promised David that his lineage would endure forever, ultimately fulfilled in Jesus Christ.

Application for Believers
For Christians, the "Key of David" is a reminder of Christ's lordship and the assurance of His control over the spiritual realm. It encourages believers to trust in His sovereign will and to seek His guidance in their lives. The symbol also calls for faithfulness, as seen in the commendation of the church in Philadelphia, which remained steadfast despite challenges. Believers are encouraged to rely on Christ's authority and to remain faithful, knowing that He holds the key to eternal life.