Legal vs Lawful

 "The law of nature is that which God infused into man's heart... our allegiance is due unto the law of nature before any judicial or municipal law: [it] is immutable" Sir Edward Coke (1608)

Black's Law Dictionary defines 'Law' and 'Lawful' as: 

LAW. That which is laid down, ordained, or established. A rule or method according to which phenomena or actions co-exist or follow each other (Black's Law Dictionary, 4th Edition, p.1028) 

LAWFUL. Legal; warranted or authorized by the law; having the qualifications prescribed by law; not contrary to nor forbidden by the law. 

It is not clear, however, who's law we are referring to. Is it the universe law; God's law; or man's law? From the definition of 'law', we can suppose an 'order' but it is by no means obvious that we are referring to a hierarchical order. We'll have to set aside these questions for now. So why is the term 'legal' included in the definition of 'lawful' as if they indicate the same? The definition continues:

The principal distinction between the terms "lawful" and "legal" is that the former contemplates the substance of law, the latter the form of law. To say of an act that it is "lawful" implies that it is authorized, sanctioned, or at any rate not forbidden, by law. To say that it is "legal" implies that it is done or performed in accordance with the forms and usages of law, or in a technical manner. 

Lawful implies a moral content beyond man, legal speaks of norms or rules made by man. Lawful can also mean man-made laws, but those have a higher dimension than a mere rule might have. 

In this sense "illegal" approaches the meaning of "invalid." For example, a contract or will, executed without the required formalities, might be said to be invalid or illegal, but could not be described as unlawful. A further distinction is that the word "legal" is used as the synonym of "constructive," which "lawful" is not. Thus "legal fraud" is fraud implied or inferred by law, or made out by construction. "Lawful fraud" would be a contradiction of terms. Again, "legal" is used as the antithesis of "equitable." Thus, we speak of "legal assets," "legal estate," etc., but not of "lawful assets," or "lawful estate." But there are some connections in which the two words are used as exact equivalents. Thus, a "lawful" writ, warrant, or process is the same as a "legal" writ, warrant, or process. (Black's Law, 4th Edition, p.1032) 

This last paragraph of the definition is crucial to understanding the difference. An act can be deemed 'legal' when it is unlawful just because it conforms with the formal aspect of laws. That is why legal fraud is possible but not lawful fraud. No one, not even a government, can give man a permit or license to do anything that is unlawful. If we can do something 'legally' with a license, we should be able to do the same thing lawfully without one. The legal aspect of law twists with formalities what is lawful. 

Moreover, 'legal' refers to the letter/science of the law (material), while 'lawful' refers to the moral of the law (ephemeral). Because of that 'divine' nature of the law, there is a foundational principle that must be respected. Ultimately, we are already free and so we can only have a system that is based in consent. 

There is another dimension to this difference... Lawful applies to the Law of the Land; while legal applies to the Law of the Sea (Admiralty/Maritime) and the Law of the Air (Cannon/Ecclesiastical). Therefore, legal applies to corporations, to fictions only. Crown (corporation) courts are private courts which are inferior to Common Law courts. Legal applies to persons, not to man and woman. The law is dictated depending on which jurisdiction one finds himself in. Therefore, 'lawful' speaks of freedom (free dominion) on the land; while 'legal' speaks of becoming bound to laws which are not of the land. 

"Statute types are "Acts, Bills, and Legislative Instruments", and they apply to artificial legal (legislated) "persons", so their texts never refer to a living "man" or "woman". Statute titles never end with the word "Law". Public officials habitually refer to "Acts" as "laws". But an "Act" is not a "Law", i.e. the Land Transport Act, is not titled the Land Transport Law." Living in the Private.