This goes deeper than the "letter of the law." It suggests that laws must be grounded in moral principles like equality and justice [3, 4]. Lon Fuller, a famous legal philosopher, argued that for people to have true fidelity to a legal system, that system must possess an "internal morality"—it must be clear, public, and applied consistently [5]. The Role of Judges and Officials
The great American judge Learned Hand captured the tension perfectly: "A society so riven that the spirit of moderation is gone, no court can save; but a society which has lost the habit of fidelity to law, no court can even serve." fidelity to law meaning
Argued that law and morality are separate. You might obey a law because it is "the law," even if it is immoral. This goes deeper than the "letter of the law