I am convinced that one reason people do not press into obeying Christ with more enthusiasm is because they do not know there are spiritual dynamics involved. If there is ignorance on that point, then we will think it a light thing to disobey on a "small" matter (like allowing yourself to make that crude remark or to grumble a bit or to have that third piece of cake against the check in your spirit). After all, we can always confess it afterward and God will forgive us, right?
There has to be something wrong with that attitude. There just has to be something very consequential to cavalier disobedience that we will be surprised at on the last day. There has to be something wrong with the calculus that because I am saved by the blood of Jesus, it doesn't matter so terribly much if I let myself slouch in my response to Jesus' commands. There are so many things wrong with that posture that it is hard to know where to start.
But this moment I am zeroing in on one tragedy in particular. That is the little-understood truth that whenever we obey God, in the minutest of matters, though nothing seems to have changed outwardly in our circumstances as a result, the reality is that something has occurred in the invisible world. In the flesh, you may still be sitting in the kitchen chatting with a group of people over dinner, just as you were in the seconds before you committed the obedient act (say, you stifled an urge to make a retaliative comment). But in actuality a slight change has been made in your soul. You have just become stronger and more like Jesus in some hard-to-quantify way. And those who have done that spiritual warfare and died that little death can feel the change in themselves. They have just become by one small degree further transformed into the image of Christ (2 Corinthians 3:18).
Likewise, if you decided to slouch and just let your mouth spout out whatever worthless word comes into your head, you do not see a difference in the physical dimensions a moment afterward: You are still sitting with your family or friends at a table; they are still passing the plate of sandwiches around. But in the spiritual domain, you have forfeited an opportunity to become more like Christ, and there is an intangible but real consequence in your soul.
There are many reasons why we should care about being very earnest to obey God and to "be perfect" (Matthew 5:48) in all the hundreds of occasions that arise in the course of a day. And if it is not enough of a reason that sloppy obedience tramples the Son of God underfoot (Hebrews 10:29), then another reason that should interest us is this: There is a spiritual dynamic going on in our lives at all times. Under the threshold of our physical observation, we are, with every choice, either becoming more like Jesus or more like his Enemy.