Carl Schmitt wrote in 1934:

We do not know on the basis of feelings, but strictest scientific insight, that all law is the law of a certain people. It is an epistemic truth that only he, who is by blood part of a law-making community, is able to see matter of facts correctly, hear testimonies correctly, understand words correctly and judge impressions of people and things correctly. From the deepest, sub-sonscious impulses of the mind, to the smallest part of brain matter, man is part of the truth of this membership of people and race. Not everyone who wants to be objective and believes with subjectively good conscience that he has tried hard enough to be so is objective. Somebody who is racially-foreign may behave ever so skeptically and try ever so keen-wittedly, may read and write books, he thinks and understands differently, because he is of a different race, and will remain in every decisive train of thought in the existential conditions of his race. [...] We seek a bond that is more dependable, more alive and deeper than the decieving commitment to twistable letters of a thousand legal paragraphs. Where else can they lie, but our own race?

And elsewhere:

The Führer protects the law from the worst misuse when he, in the face of danger, makes use of his position as highest judge in order to create law [...] The true Führer is always also judge. [..] Those who try to seperate the two or even turn them against each other either makes the judge a counter-Führer or a tool of a counter-Führer and seeks to dismantle the state with help of the legal system. [...] In truth, the deed of the Führer [Night of the Long Knifes] true jurisdiction. It is not subject to justice, but was itself highest justice.

The legal system was to break with core principles of a "bourgeois rule of law". In the words of Hermann Goeringa young faculty assistant from the university of Breslau:

Weak consideration of the individual wll, contrary to the liberalist [sic] state, not be taken anymore. Against the lawbreaker, the enemy of the state and People's Community there is only one thing in degree and enforcement of penalties: Powerful strictness and, if necessary, total annihilation. We have finally learned that the form of head and other racial make-up of man are neither accident nor unimportant, but expression and basis of his innermost feeling and desire.

Another important aspect is the "völkish" loyalty, which was supposedly rooted in the basis of the people:

National Socialist criminal law shall be based on the völkish duty of allegiance: Duty of allegiance is for NS and German thinking highest völkish and therefore ethical duty. In German thinking, there is unison between ethical evaluation, feeling of duty and sense of justice. [...] Job of the NS-state is to punish the breaker of loyalty, who by his action has been expelled from the Community, through a just expiatory punishment. Just punishment serves the consolidation, protection and security of the People's Community, but also the education and improvement of the criminal and not-yet-lost comrade.

Therefore every crime was not only that, but a breach of loyalty against Führer and People. If you broke a law, you were outside of the People's Community, a traitor and enemy of the people. Not the crime, but the personality of the criminal was important in considering if it was worth it to try and reintegrate them into the People's Community or if they should be eliminated instead.

The job of the lawyer was also reinterpreted. Instead of representing the accused, they were now "moved closer to the state and community".

I hope this helps somewhat in understanding NS legal theory, whose three pillary may be identified as the role of treason/breach of loyalty, the People's Community and state being put before the individual and the Führer standing above all justice, not being subject to it, but creating it instead.

I took my information and quotes from Helmut Ortner: Der Hinrichter. Roland Freisler - Mörder im Dienste Hitlers. 2013

At the point it was set down it was a meaningless echo from the public debate over the introduction of the BGB lawbook, based on the Roman law as transmitted by Gaius, in 1900. It replaced many local systems, sometimes in use from the middle ages, which were referred to as "gemeines recht" - "common law" or "the law of the land".

During the nazi era these words were defined anew to fit whatever was the big thing at the time.