1 Peter 5:8-9
Be of sober spirit, be on the alert. Your adversary, the devil, prowls around like a roaring lion, seeking someone to devour. But resist him, firm in your faith.

Ephesians 6:11-12
Put on the full armor of God, so that you will be able to stand firm against the schemes of the devil. For our struggle is not against flesh and blood, but against the rulers, against the powers, against the world forces of this darkness, against the spiritual forces of wickedness in the heavenly places.

The more we do for God the more agitated the devil will become and the more he will attempt to mess up our life. The main thing he does with me is talk to me, and I hear him in my thoughts. His goal is to get me to believe lies so I will act on those instead of truth. He increases the volume, that is the number of times he or his demons speak to me, the number of thoughts that pop into my thinking, and I suppose the loudness as well. I would guess that he accomplishes that by increasing the number of demons assigned to me.

I resist the domain of darkness by choosing to rejoice always, setting my mind on verses I have memorized and thinking about them a lot. Sunday nights are almost always nights of great struggle to take my thoughts captive to the obedience of Christ, and to not let my thoughts drag me into self-pity, irritation, bitterness, weariness, and a host of other thinking patterns designed by the devil to steal my joy.

Sometimes I get weary with the unending onslaught of negative thoughts that I need to conquer. The Bible promises that there comes a point that if I am faithful to keep resisting that he , the devil, will flee from me for awhile.