Isaiah 22:20-25, John 20: 19-23
Holding the key means being in control; having the authority to open and shut, the ability to grant entrance through the gate. Isaiah prophecies that there will be one who comes with complete authority. Upon him, God will bestow the key of David. The kingdom gates he will open, and none will shut. He will shut, and none will open.
Jesus himself also made use of this symbol, showing the prophetic relationship of the earthly kingdom of David to the kingdom of God. All power and authority was given to him after the resurrection; Christ holds the key.
Following his glorious resurrection, Christ entrusted this power to “bind and to loose” to Peter and the ministers of his church. This Office of the Keys, the authority to bind and loose is bestowed upon the Church. Yet, even as Christ authorizes such binding and loosing, he alone has the power to forgive sin and reconcile God’s people. So the Advent Church sings:
O come O Key of David come,
and open wide our heavenly home.
Make safe the way that leads on high,
and close the path to misery. Rejoice!
O Come, O Come, Emmanuel v. 5 Traditional