So the law is holy, and the commandment is holy and righteous and good. (ESV)
When your child is punished for doing wrong there are a couple ways that they can respond. A child may look at their punishment and resent their parents for the discomfort brought to them. They can blame the parents. After all, if they would not have punished them they would not be in discomfort. This view assumes that the "law" given by the parents is evil because it brought them pain.
That childlike view is foolishness. As a parent I am sure that if your child responded to the punishment they received by resenting you, you would not be impressed by their folly. You would likely explain the reason for their punishment in greater detail so that they can understand just how proper your rules were that were broken.
Consider our view regarding God's Law. We sin against God and receive the natural punishment that is due those who violate God's Law. We can either resent God for his just treatment of our violation of his Law or we can humbly repent of our sin, recognizing the holiness of God's standard. The issue at stake is whether or not God's law is holy.
Paul makes very clear here in this verse that God's law is holy. It is righteous. It is good. Quite simply, we know that God's Law is good because it proceeds from him. If we have a proper understanding of the character and nature of God we know that everything that he does is perfect, holy and righteous. I may not like it, but that speaks more of my wrong perception.
God's Law is holy. The more I look at God's Law the more I will see a righteous and holy God. If you have been found to be unholy in relation to his Law repent of your sin and receive the forgiveness freely offered to you in Christ Jesus.