The God of peace will soon crush Satan under your feet -Romans 16:20
In William Gurnall's classic book "The Christian in Complete Armour", he gives much practical advice to Christians. This little snippet is encouragement for us when our peace is robbed.
"When Satan comes to take away your peace, if you do not understand the full significance of your justification in Christ you will be easily overcome. A saint without assurance of salvation is as unprotected as the rabbit that darts into a thicket to escape a fox, but is easily followed by the print of her own feet and the scent she leaves behind. In Christ you have a hiding place where the enemy dare not come: 'the clefts of the rock, in the secret places of the stairs' (Song of Sol. 2:14). While the devil may be in hot pursuit of your soul, the very scent of Christ's blood, by which you are justified, is noxious to him and will stop him in his tracks. Run straight into this tower of the gospel covenant, and roll this truth on the head of Satan, as the woman cast the stone on the head of Abimelech: 'To him....that....believeth on him that justifieth the ungodly, his faith is counted for righteousness' Rom. 4:5
Lifted from my Fahdur's blog