Christ Himself is the tower, Himself for us has been made a tower from the face of the enemy, who is also the Rock whereon has been built the Church. Are you taking heed that you be not smitten of the devil? Flee to the Tower; never to that tower will the devil's darts follow you: there you will stand protected and fixed. But in what manner shall you flee to the Tower? Let not a man, set perchance in temptation, in body seek that Tower, and when he shall not have found it, be wearied, or faint in temptation. Before you is the Tower: call to mind Christ, and go into the Tower.
Augustine, Enarrationes in Psalmos 61 (i.e., what we usually call Psalm 60)
