Fourth Antiphon –
December 20th: O Clavis David
O Key of David, O royal Power of Israel, controlling at your will the gate of heaven, Come, break down the prison walls of death for those who dwell in darkness and the shadow of death, and lead your captive people into freedom
The Lord Jesus is invoked here as the Key of David, the one who can open the gate into the kingdom because he is the gate. He knocks at the door of our hearts leading us out of the darkness of sin into the true freedom of the children of God, which is freedom from sin and the resulting joy and delight.
 Is. 22:22
 Luke 1:79
 Rev. 3:7
 cf. John 10:7
 Rev. 3:19
For more visit: O Antiphons Reflections from Fr. Giles Dimock O.P.
The O Antiphon reflections are from Musings: Liturgical and Charismatic authored by Fr. Giles Dimock, O.P. and published by Discerning Hearts®
You can find the book here