-- Lk 12:35-38
Such a battle and such a victory become possible only through prayer. It is by his prayer that Jesus vanquishes the tempter, both at the outset of his public mission and in the ultimate struggle of his agony. In this petition to our heavenly Father, Christ unites us to his battle and his agony. He urges us to vigilance of the heart in communion with his own. Vigilance is "custody of the heart," and Jesus prayed for us to the Father: "Keep them in your name." The Holy Spirit constantly seeks to awaken us to keep watch. Finally, this petition takes on all its dramatic meaning in relation to the last temptation of our earthly battle; it asks for final perseverance. "Lo, I am coming like a thief! Blessed is he who is awake."
-- CCC 2849