2 Chronicles 30:
27 Then the Levitical priests arose and blessed the people;
And their voice was heard
And their prayer came to His holy dwelling place,
"Prayer is the never-failing response of the Christian in any case, in every plight. When you cannot use your sword, you may take up the weapon of prayer. Your powder may be damp, your bowstring may be relaxed, but the weapon of prayer need never be out of order. Satan laughs at the javelin, but he trembles at prayer. Swords and spears need to be sharpened, but prayer never rusts; and when we think it most blunt, it cuts the best. Prayer is an open door that no one can shut. Devils may surround you on all sides, but the way upward is always open, and as long as that road is unobstructed, you will not fall into the enemy's hand."
Finish Reading Alistair Begg's, Weapon of Prayer