James 4:7, Submits yourselves, therefore, to God. Resist the Devil, and he will flee from you.
How ought the Devil and his demons to be resisted? Exactly how Christ resisted him in the desert: with the Word of God. Yet beware, for he will return with more temptations and doubts at an opportune time (Luke 4:13). And why does the Devil flee? Though he will twist God’s Word to trick weak minds, he cannot resist the Word, for he is terrified of God.
Proclaim the Word of God against the Devil, and he shall flee. Then prepare for another attack, for his hatred for you and all God’s creation is indefatigable. He kills and deceives because it brings him pleasure. Imagine the worst psychopath; Satan is profoundly worse.
Do not fret, O Christians. Though the Devil and his demons seek to destroy you, they cannot harm you, for you are a baptised child of God, indwelled with the Holy Spirit. Therefore, they are afraid of you. Thus, if you see a demon, say, “Ha! Stupid demon! I am baptised into Christ! What can you do to me?” And if it pesters you, sing hymns until its ears bleed. If you know of none, learn and sing the doxology:
Praise God from whom all blessings flow! Praise Him all creatures here below! Praise Him above, ye heavenly hosts! Praise Father, Son, and Holy Ghost! Amen!”
Sing it a hundred times if you must, for the Devil and his demons tremble at the sound of God’s Word and cannot bear to hear such joyous singing.
The Lutheran Column 