"For the law having a shadow of good things to come, and not the very image of the things, can never with those sacrifices which they offered year by year continually make the comers thereunto perfect." Hebrews 10:1
If the law is a shadow of the good things to come, then, being a shadow, it has no substance because only the real image, of which the law is a shadow, has substance. The shadow changes nothing because it is has no substance: only the image has the capability of bringing about any change. To trust in the shadow to bring about change is futile because shadows only indicate the nearness of the image, which alone is able to effect change. That image is Christ.
Each time you see a shadow, you are reminded of the nearness of the image. In the same way, each time you see the law, be reminded of Christ, the image. How frustrating it can be when you attempt fixing a problem by means of a shadow. As ridiculous as this is, sadly, this is what we attempt doing each time we depend on the law to fix the problem of sin. It simply doesn't have the capacity to do it, only Christ does. When we use the law lawfully, it will always point us to Christ as the solution to sin.
Toni