Satan also works in the human heart.
Upon first Believing in the Lord you may feel very happy, joyful and peaceful.
But if you are not Watchful – being ignorant of what the enemy can do – you will find yourself one day mysteriously uncomfortable.
You feel somewhat restless today, somewhat unhappy tomorrow, and somewhat depressed the day after.
Little by little, your peace is completely lost, your joy totally gone.
This is the way the devil wears you down to a state of fatigue and despair.