Although we may be completely oblivious to it, we are all alive because the Spirit of God breathed into our lungs. Everything we do is determined by spirit.
Walk down the street with a (honest) smile. You may observe other people brightening as they pass you. If you wear a grim visage, you may notice a similar thing happening to others. The spirit that commands us affects not only other people but all facets of the environment in which we live.
(I have a friend my age who for many years has worked for the
Dale Carnegie Institute. He strikes me as having spiritual power equal to that of most church members I know; however not to that of a commited Christian. He has made a good living and has a lovely wife and several healthy children.)
When I visit the hospital, I find patients with many various demeanors. A certain number of them greet me with a smile. I sense the presence of the Spirit there, and our meeting, conversation, prayer is joyous and effectual. Others, although having the physical capability to smile, lack one. I sense the presence of "spiritual wickeness in high places" affecting those sufferers, and there is some spiritual cost to minister to them.
In the (relative) absence of God's Spirit, a dark spirit moves quickly and effectually into the environment. But when we take on the full armor of God (Epesians 6:11ff), that other spirit departs quickly. Praise God. Be joyful in the Lord.