Of old, prayer was able to rescue from fire and beasts and hunger, even before it received its perfection from Christ. How much greater then is the power of Christian prayer. No longer does prayer bring an angel of comfort to the heart of a fiery furnace, or close up the mouths of lions, or transport to the hungry food from the fields. No longer does it remove all sense of pain by the grace it wins for others. But it gives the armor of patience to those who suffer, who feel pain, who are distressed. It strengthens the power of grace, so that faith may know what it is gaining from the Lord, and understand what it is suffering for the name of God.
In the past prayer was able to bring down punishment, rout armies, withhold the blessing of rain. Now, however, the prayer of the just turns aside the whole anger of God, keeps vigil for its enemies, pleads for persecutors. Is it any wonder that it can call down water from heaven when it could obtain fire from heaven as well? Prayer is the one thing that can conquer God. But Christ has willed that it should work no evil, and has given it all power over good.
-From the treatise On Prayer by Tertullian