I have to give a little heads-up to the gentleman readers: this posting will touch on a topic that's probably not your favorite. Not to worry, I'll keep that part brief.
When I moved in with my sister last year, we began to "sync up." You might have heard this term before. Evidently, when women spend significant amounts of time together, their cycles tend to "sync up" with each other such that the women will ovulate/menstruate at the same time. There are several theories that attempt to explain this phenomenon, but a deep understanding of the science behind it isn't really necessary for my point. In essence, a woman can sense another woman's hormonal cycles and will readjust her cycle accordingly. Of course, the women are entirely unaware that this is happening. I recently moved in with a group of ladies, and we jokingly discussed how long it would take for all of us to start "syncing up." Other than just being a very strange phenomenon, I think it is also a useful analogy for the spiritual world.
Think about what happens in a woman's body when she ovulates/menstruates: it involves a complicated system of delicate processes that even changes in stress levels, exercise, weight gain/loss, etc. can frustrate. Just being in the same apartment as my sister (and most likely with my new housemates) has caused this entire system within me to rearrange itself. And I haven't been aware of these changes for even one second. Remarkable!
Many people, if they believe in a spiritual world at all, think that whatever is happening "out there" doesn't have anything to do with us. We go about our daily lives usually not giving a second thought to the spiritual world. No doubt, a major reason why it's so easy to ignore is because we don't usually experience the spiritual world with our senses; we are hardly ever conscious of it. And, unless we seek it out and/or pay special attention to it, we often can't tell when we've been affected by the spiritual world. So we mosey along oblivious to it all.
But the Bible tells us that not only is the spiritual world real, it is more real than the physical world. The beings of that world are powerful, personal, and motivated to interfere with our lives. God is Spirit. We have no need to worry about what He's up to. But what about our enemy? Is there any reason to be on guard? I think so. To be sure, the Bible says that we "do not wrestle with flesh and blood." The true enemies of our souls are spiritual beings. And they are prowling about us "like a lion, seeking whom [they] may devour." Thankfully, we have protections against this. Through Jesus Christ, we can overcome our enemy. Once again, scripture brings us back to the spiritual world. The Bible explains that our weapons "are not carnal" (not physical weapons), but are "mighty through God" (Spirit).
In short, the spiritual world--though invisible--is a constant reality. Every day, spiritual things, beings, and phenomenon are buzzing around us, potentially affecting everything we do. Again, think about the menstrual cycles discussed above: major changes can be happening within/around you, and yet you aren't the slightest bit aware of it. Our obliviousness to the spiritual world doesn't minimize the impact it can have. Add to that, spiritual beings are not just biochemical processes. They are living entities with real personalities. And they are actually trying to influence us--for better or worse.