James 4:7

Submit to God. Resist the devil and he will flee from you.

Somedays, we have to set the devil running with the word of God.  Those days he is shooting dart after dart at us remind him how big of a God we have and what the word says about us.  Resist the thoughts that come to the mind and cast down the imaginations that he tries to put in the brain.  Speak the word and keep speaking it until he gets the points and leaves you alone.