O Antiphons: O Key of David This Sunday is the First Sunday of Advent, and the “O Antiphon” we consider this week is the Lord’s Messianic title, “O Key of David.” The antiphon for Vespers is: 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 Alleluia for Mass modifies it as, “O Key of David, opening the gates of God’s eternal Kingdom: come and free the prisoners of darkness!”...