Your enemy is driven back by the Word of God spoken from your mouth. This is your weapon- a powerful, two edged sword able to pierce dividing asunder of soul and spirit, of joints and marrow, and is a discerner of the thoughts and intents of the heart. Speak God's Word and hide it in your heart daily. It will serve to combat the enemy.
2 Corinthians 10:3-6 declares, "For though we walk in the flesh, we do not war after the flesh: For the weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds; Casting down imaginations, and every high thing that exalts itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ; And having in a readiness to revenge all disobedience, when your obedience is fulfilled."
The Word will drive back the sinful nature. The Word will purify your thoughts and keep your actions holy. The Word is your greatest weapon against the enemy. So drive back your enemy with the Word of God read and spoken daily over your life!