While the the old ceremonial law of ordinances have been nailed to the cross, Christ having fulfilled all, Jesus lifted the moral law out of the domain of the natural and carnal realm into that of the spiritual.
Paul called the moral law given to Moses on the mountain, holy, just and good. But then in
Rom 7:14 he called it "spiritual." The law lifted from the carnal state, though holy, just and good is seen in a new light that Jesus brought to this law, making it spiritual.
Much can be said about this but this would not be the place to delve too deeply into it. However, David being both King and Prophet understood this "spiritual" concept of the carnal law. It occupied his thoughts continually. With each new discovery wrought in his mind from the marvelous light that burst forth as the horns of a rising sun, he was obsessed with going further into the unsearchable regions of the worth, value and expanse of the "spiritual law."
But, on the other hand, we are never too far away from the hiss of the serpent in the tree of knowledge...."sssss...thou shalt not surely die...." The wise man will turn from hearing the hiss and will turn to the tree of life and wonder at the life-giving powers in the fruit from it's tree...the law of the Lord.
"Thy Word, have I hid in my heart...."