No person born of God will habitually and characteristically continue in sin, and is therefore we are kept from Satan’s harm. The doctrine behind this has clearly been laid out in the previous verses. Although we all stumble we will feel conviction and repent, and we will daily become more like Christ. Although we may be assailed by Satan and the sinful world around us he cannot destroy the life and hope that is within us. True believers are safe in the grace of God and cannot lose their salvation.
The world around us lies in the power of the evil one, often unknowingly doing his bidding. There is no desire to through off the fetters that bind. In the majority of the world the dominion is complete. Individuals and nations are entirely subject to his will, imagining all the while that they are their own master. In many passages it is supposed that Satan has been given some amount of control over the world, especially the pagan world and false religions (John 12:31, 1 Cor. 10:20, 2 Cor. 4:4, Eph. 2:2, 6:12). It is our task to fight against the forces of spiritual darkness, knowing that no matter how hopeless the battle may seem that we are on the winning side!