God promises peace to those who do His will.
There is a deep inner peace that reigns in us when we do what God tells us to do. There is a quietness and an assurance. It is called the peace that passes all understanding. It is not a worldly, fleeting peace. It is peace that remains. It is peace that reigns regardless of circumstance.
We are not to be anxious or worry about anything, but instead we are to pray about everything. We are to lift up our cares unto the Lord and let Him take them, trust Him to take care of us, trust Him to make it all work out. All things work together for good to them that love God.