O Key of David, and scepter of the House of Israel: you open and no one shuts; you shut and no one opens. Come and lead forth from his prison the captive sitting in darkness and in the shadow of death. Amen.
The key is a symbol of authority. People with authority are found in offices and palaces; they are great and they make their influence felt. Who would have thought to look for power and might in a stable? And yet this baby is the key for the salvation of the whole world. A locked door cannot be opened without a key; heaven's gates were closed until the promised Messiah would come and pay the price for our sins. Come, O Key of David!