Worry gives each of us a little sense of anguish we don't really need to experience, but somehow we continue in our own person "anguish" and don't really let go of things we don't need to be focusing on. Why is that? I think it may be either because we think we "deserve" the anguish, or we just have issues with letting go of the control we want to maintain in life. Either way - it is foolish for us to live in worry. Fear or dread is one of the natural responses we are given as a result of certain "senses" which kick-in various hormone responses in our body. We are a little less in control of when fear may "kick-in", but we are capable of having equally as much impact on how long we allow fear or dread to "rev-up" those hormones within us. Worry is usually because of uncertainty of some kind, while fear or dread is usually in the face of what we interpret to be "literal" threats to our lives in some way. We heard the screeching of tires behind us, only to look in the rear view mirror to see a large truck stop within centimeters of our rear end - that is a real sense of dread - it is something we literally experience. Worry is almost an internal kind of thing which we "manufacture" based on the "what-if" scenarios we can imagine in our minds. Either of these can be damaging forces for our minds and bodies, but both are responses God wants us to learn to get "under his control".
You won’t need to worry about dangers at night or arrows during the day. And you won’t fear diseases that strike in the dark or sudden disaster at noon. You will not be harmed, though thousands fall all around you. And with your own eyes you will see the punishment of the wicked. The Lord Most High is your fortress. Run to him for safety, and no terrible disasters will strike you or your home. (Psalm 91:5-10 CEV)
Things which go bump in the night can give all of us a little fright. I have been awakened from sound sleep by loud noises, voices outside, and barking dogs. When I lived alone, those sounds were amplified like 1000% because being alone and hearing noises from "unknown" sources is kind of creepy! Once awakened, what happened? Yep, you guessed it, sleep came hard again. Why? My internal "juices" (hormones) were in the flight mode! They got stunned into action and it takes a while for the body to shut down, ridding itself of the mess of hormones released when fear begins to mount. As soon as I realized the "source" of the noise (like it being the neighbor dumping his trash at 11:30 at night while wildly banging the trash can against the trash dumpster), we can begin to settle those internal responses, but the "damage" of those "juices" already flowing around in your body is simply something which takes time to overcome! This might be the tremendous blessing God gives when we refuse to allow fears to mount in the first place - we don't have to go through the rebound phase of "coming down" off our emotional fear high!
Much of what our psalmist describes are those things we cannot predict, or even rationalize. They are situations and circumstances often out of our control - like dangers in the night, diseases we cannot see, and sudden disasters like the truck barreling toward our car's rear end. As long as God has become our fortress, these things may attempt to strike us down, but they are unable to do so because our lives are securely placed within the "garrison" of his care. I play a computer simulation game which starts out making you develop colonies of people, complete with finding resources such as lumber to build with, mines to find valuable ores which will help you fashion additional tools and have trade coins, and foodstuffs from animals you hunt or ponds you fish. As the game progresses, you have to keep upgrading your towns and the "garrisons" you place around them can make all the difference if you are not quite ready to form alliances with other "peoples" in your immediate area. Without those garrisons, the other peoples may just invade your fields and take your much needed resources.
Try as I might, on occasion I build a mighty town and it has stones walls. I develop armies of men who will act as my protectors of that community I have created. Yet, if I fail to erect sufficient defenses, even the stone wall I erected may be insufficient to hold off the invading forces from without. I may have missed the opportunity to develop my armies fast enough, or I don't erect defensive guard towers to alert me to approaching forces. I take my eye off the happenings around me because I am so focused on something I want to create or do within my own little section of territory I neglect to see how well advanced those surrounding me have become! This is kind of what it is to live life just "inside" our own little fortress we call "self". We think we have adequate defenses against the stuff which will come against us, but if we are totally honest here, we often don't realize how powerful those things which are coming against us are, nor how stealthily the have prepared to invade! No wonder we have those responses of fear and dread, worry and anguish! We have been distracted, caught up in what we think are pretty reliable "defenses", and oblivious to the real dangers which surround us.
This is why it is important to have the right "fortress" - God himself. It isn't about the volume of the defenses - it is about the quality of that defense. It isn't about the existence of resisting forces - it is about the presence of defensive resources within! No other fortress will give us the sense of security and peace that God will - just sayin!