|You will keep in perfect peace|
him whose mind is steadfast,
because he trusts in you.
|Thou wilt keep him in perfect peace, whose mind is stayed on thee: because he trusteth in thee.|
The mind is hard at work all day long, a powerful organ that keeps your body on the task at hand.
It's easy to allow our minds to focus on worldly activities, places, and people that don't honor God. When we focus on anything that separates us from God and don't trust Him, we can become restless.
Yet when our minds are focused on the Lord and trusting Him with our lives, He keeps us in His peace, His blessed peace.