Our physical world is bound to a spiritual one with powers at play deeper than we can see and more powerful than we can wholly comprehend.
Paul reminds us to live aware of this dual reality, confident in the knowledge that only in Christ are we fully equipped to wrestle the spiritual darkness at work around and within us, meeting it with victory.
Finally, be strong in the Lord and in the strength of his might. Put on the whole armor of God, that you may be able to stand against the schemes of the devil. For we do not wrestle against flesh and blood, but against the rulers, against the authorities, against the cosmic powers over this present darkness, against the spiritual forces of evil in the heavenly places.