The reason we must put on the whole armor of God is to withstand evil. We don’t war against people, but against a spiritual hierarchy of invisible power. The forces of evil are invisible powers with a structure and specific levels of authority. We are not only to use our armor to protect and defend ourselves from them—as important as that is—but also to go on the offensive against them as well. When we do that, we close doors to the enemy and open doors to the will of God to be done on earth. We