Prayer is the wall of faith: her arms and missiles against the foe who keeps watch over us on all sides. And, so never we walk unarmed. —Tertullian, On Prayer
2 Corinthians 10:4 (NIV) The weapons we fight with are not the weapons of the world. On the contrary, they have divine power to demolish strongholds.
Elesha Hodge, comp., Today's Best Illustrations – Volumes 1-4, (Carol Stream, IL: Christianity Today, 1997), WORDsearch CROSS e-book, Under: "PRAYER".