Romans 7:8-13
"But sin (our Sinful Nature), seizing the opportunity afforded by the commandment (the Law), produced in me every kind of covetous desire. For apart from law, sin is dead. Once I was alive apart from law; but when the commandment came, sin sprang to life and I died. I found that the very commandment that was intended to bring life actually brought death. For sin, seizing the opportunity afforded by the commandment, deceived me, and through the commandment put me to death. So then, the law is holy, and the commandment is holy, righteous and good. Did that which is good, then, become death to me? By no means! But in order that sin might be recognised as sin, it produced death in me through what was good, so that through the commandment sin might become utterly sinful."
Romans 7:8-13 teaches us the incredible and seemingly paradoxical Truth that the Law, instead of making us more righteousness, actually makes us more sinful! By way of illustration, when you are told not to do something, though you may have never thought of doing that thing before, now there is awakened in you, by your Sinful Nature, the desire to do that very thing! As Paul wrote, "through the commandment sin ... becomes utterly sinful."
That is why Legalism does not work. The Laws, rules or regulations act as red capes to the raging bull of our Sinful Nature, inflaming its desires to a greater intensity and defeating the very purpose we sought to achieve.