What was the Law of God Before Moses and How was It Disseminated?

While there is no shortage today of anti-dispensationalism in the church of Jesus Christ--with some preachers and teachers averring that Dispensationalism is false teaching, there is still something to be said for the legitimacy of its theology.

Though not a rabid dispensationalist myself, in my opinion the teaching regarding Dispensationalism's "Age of Conscience" can go a long way to answering your question about the existence and role of the Law of God prior to Mosaic law.

From Compelling Truth:

Dispensationalism is a system of theology that organizes history into different periods, or "dispensations," of how God works. It is a way of looking at God's plan for specific periods in history to roll out the revelation of Himself and His desire for relationship with people.

Of the classic seven dispensations, or ages, the dispensation of conscience (Genesis 3:23 to 8:19) is second after the dispensation of innocence (Genesis 1:27—3:19) in which God interacted with the first humans face to face.

Each dispensation is said to have a six-part pattern. For the dispensation of conscience, the pattern is:

Managers: Cain, Seth, and their families Time Period: Expulsion from the garden of Eden until the Flood, about 1,656 years Human Responsibility: Do good and offer blood sacrifices (Genesis 3:7, 22; 4:4) Failure: Wickedness (Genesis 6:5–6, 11, 12) Judgment: Worldwide Flood (Genesis 6:7, 13; 7:11–14) Grace: Noah and his family are saved (Genesis 6:8-9; 7:1; 8:1)

The end of the first dispensation, that of innocence, came about when Adam and Eve disobeyed God. God then instituted conscience as a way humans could delineate between good and evil, choose good, and have a relationship with God through blood sacrifice (Genesis 4:4). Almost immediately, people chose evil. Cain killed Abel (Abel was the first person ever to die) because God accepted Abel's animal (blood) sacrifice but did not accept Cain's grain sacrifice. Cain had a choice, clearly communicated by God (Genesis 4:6–7), to choose good in obedience. Cain refused, expecting God to fall in line with his own ideas of how to have a relationship with Him.

Mankind did not fare well, violating . . . conscience and failing to do what was right. Evidently God wanted to demonstrate to mankind that conscience cannot be our only guide. During the dispensation of conscience, only three people were declared righteous—Abel, Enoch, and Noah (Hebrews 11:2–7; Genesis 5:22–24; 6:8–9). Before the Flood, "The LORD saw that the wickedness of man was great in the earth, and that every intention of the thoughts of his heart was only evil continually" (Genesis 6:5).

Because Noah was righteous, God chose him to warn others as he built the ark for 120 years (Genesis 6:14–22; 2 Peter 2:5). None heeded. God righteously judged the sin of people and they suffered the consequences of their choices—but the human race also experienced God's mercy. God spared Noah and his family (Genesis 7:1; 8:1; Hebrews 11:7), showing how He could and would "rescue the godly" (2 Peter 2:4–10). A new dispensation began (that of government)]1 (my emphasis).

A close reading of Genesis 4 serves to illuminate the ways in which human conscience is informed by God's "thou shalt nots" and God's "thou shalts," even before God codified those do's and dont's in the Law of Moses.

Those ways would have to include the role and effects of parental instruction on children, particularly the inculcation of values via each parent's sound teaching and consistent role modeling. We can only speculate about the nitty gritty of how this process functioned in the first millennium of human history. We can, however, mine for clues in the biblical narrative.

First, Adam and Eve undoubtedly taught their first two sons about the singular role that God should play in their lives, both ethically and morally. Not only were the eyes of their parents opened to the existence of both good and evil (a Hebrew merism), but every child born to the human race after the Fall has an innate sense of right and wrong, good and evil.

Notice what God said to Cain after God did not look with favor upon his offering:

"If you do what is right, will you not be accepted? But if you do not do what is right, sin is crouching at your door; it desires to have you, but you must rule over it” (Genesis 4:7 NIV).

"Do what is right," God told Cain. That takes care of the "do's" in the Age of Conscience. On the other hand, "If you do not do what is right, sin is crouching at your door" takes care of the "don'ts" in the Age of Conscience.

Whether or not Cain's parents ever told him about the time that God clothed them with skins of animals is an unknown. It stands to reason, however, that Abel somehow knew of the importance of offering up to God an animal whose blood was shed. Cain, too, likely knew of the significance of an animal sacrifice but chose instead to offer up to God "the fruits of the soil."

Abel was in no way superior to Cain, just because he kept flocks. Neither was Cain superior to Abel because he was a farmer. A legitimate assumption is that they both were taught by their parents the value of work and honest labor. Again, one of those "oughts" that comes with having been created in the image of God.

Another indication of the presence of innate laws within the breast of every image bearer is Cain's recognition that he deserved punishment for having killed his brother. Yes, he protested the severity of God's punishment, but graciously the LORD marked Cain, and with that mark, people who saw it would know he was off limits. Even though he committed murder, God would not allow anyone to murder him. To God and to His image bearers, the murdering of a human being has been and will always be wrong.

One indication the Age of Conscience was temporary and clearly not workable is the reaction of Lamech, the first bigamist, after having "killed a man for wounding. . . [him],and a young man [i.e., likely a young warrior] for injuring . . . [him] (4:23]. From the NET Bible:

Lamech seems to reason this way: If Cain, a murderer, is to be avenged seven times (see v. 15), then how much more one who has been unjustly wronged! Lamech misses the point of God’s merciful treatment of Cain. God was not establishing a principle of justice when he warned he would avenge Cain’s murder. In fact he was trying to limit the shedding of blood, something Lamech wants to multiply instead. The use of “seventy-seven,” a multiple of seven, is hyperbolic, emphasizing the extreme severity of the vengeance envisioned by Lamech.

The generations of humanity that preceded God's giving of the Law to the children of Israel were not without an inner witness about the rightness and wrongness of behavior. That inner witness, or conscience, was far from perfect, to be sure, and as observed by the writer of Compelling Truth, the Age of Conscience produced only three people whom God declared righteous: Abel, Enoch, and Noah.

True enough, God did something in the early days of humanity that He does not seem to do today: Occasionally He spoke to His image bearers, encouraging them to do the right thing. However, that so many people violated their consciences, and humankind--with the exception of Noah and his family--became so sinful that God had to destroy them and save a mere eight, meant that when God started over with only eight souls, He would need to usher in a new dispensation, the Dispensation of Human Government. After that came the Dispensation of Law.

In conclusion, humankind has never been without the inner witness of conscience, even though conscience is clearly fallible. Nor has humankind ever been without some sort of human government, no matter how primitive it may have been. And where would Western Civilization be without its common law heritage? Conscience, government, and law--each has its place, but each one is at best imperfect. What is greater than all of them is the reign and rule of Jesus in the hearts of his image bearers.

Ancient Culture To first give some cultural background to this answer, we recall that in previous centuries, the Liberal Schools mocked the authenticity of the Pentateuch, by alleging that Moses could not have written the Torah because there was "no written language at that time!" Archaeology and subsequent anthropology research proved them greatly erroneous.

Not only were there intelligent communication skills--and systematized languages--but there were records kept of commerce, international treaties, histories of battles, and inheritance rights. And also discovered were ancient CODIFIED LAWS in several of the Mideast nations! And these pre-dated Abraham and Moses by hundreds of years.

Code of Urukagna 2380-2360 B.C.
Code of Ur-Nammu, king of Ur, 2050 (Sumerian)
Laws of Eshnunna, 1930
Codex of Lipit-Ishtar, of Isin, 1870
Codex of Hammurabi, 1755-1750 (Akkadian)
Hittite Law Code of Nesilim 1650-1500.
Also consider the Ebla Tablets

Reliance on 'Oral Code'? In light of this, it is NOT reasonable to "assume" that religions--including the YHWH sect--never had written religious tenets (precepts, commandments, and laws)...even though we have only the Mosaic Laws extant...as well as references to previous commandments in the Torah which Moses wrote down.

Other religions had numerous records of their ceremonies, prayers, liturgy, and priestly requirements, during the time period of the Patriarchs, and later, the Mosaic era. Note all the hieroglyphics of the Ancient Kingdom of Egypt! Many of the carvings were on Temples re their religion. Notice the cunieform carving of Mesopotamia, even giving their rendition of the Flood! The Ebla Tablets have written references to god (El) as well as personal names similar to the biblical names.

Recorded Laws of God Although several cultures have "oral traditions" it is unthinkable that Jehovah God would expect His followers (disciples) to rely on man's memory alone, to disseminate His precepts, commandments, and laws. Nor would the consciences of fallen men remain reliable for transferring God's precepts. With all the other recorded religious cultural milieu surrounding the Patriarchs, it is a stretch to conclude that YHWH-ists would not write down important Laws of God.

The King of Salem, Melchizedek, would certainly have had access to writing implements with which to convey God's laws (YHWH, God Most High, Creator). It would be hard to conclude that Melchizedek, as priest of God Most High, was performing rituals merely by "oral tradition." (Genesis 14:18-22)

Summary The Torah is a summary of ancient Jewish history. It does not go into depth in many areas we would wish, but skips across like pebbles on the pond of redemptive history. It is not like the writings of the historian, David McCullough the American historian, who fills pages after pages of details on a single patriotic individual!

The nature of the climate, wars, and fires, earthquakes, and other causes, have reduced the number of extant records of Laws--and obliterated others. Some have been mislaid...even in the crevices of the Temple! (2 Kings 22:8) However, to make sure Redemptive History progressed faithfully, God has had continually taken the initiative to speak into human history when needed! He has spoken. He has appeared. He has acted. He has shouted. He has restored... And He will come again. [Some say He continues to speak!]

Addendum Along with lost records of Laws, keep it in perspective by recalling the great number of Books mentioned in the Old Testament (Tanakh) that are not extant! (Book of Wars, Book of Jashar, Acts of Solomon, History of Nathan, Prophecy of Ahijah, Chronicles of Gad,, Visions of Iddo, Chronicles of Shemaiah, etc.) But as the dictum in the book of Moses stated, there is enough in our possession to know God...and live a righteous life:

The secret things belong to the LORD our God; but the things revealed belong to us and to our children forever, that we may follow all the word of this Law. (Deuteronomy 29:29)

The phrase in Gen 26 may be another way of saying what was already said in Gen. 18:19, which refers to keeping "the way of the Lord." God declares that said Abraham kept this way by doing righteousness and justice, in contrast to the people of Sodom and Gomorrah.

I have chosen him, so that he may command his children and his household after him to keep the way of the Lord by doing righteousness and justice, so that the Lord may bring upon Abraham what He has spoken about him.” 20 And the Lord said, “The outcry of Sodom and Gomorrah is indeed great, and their sin is exceedingly grave."

However, The Cambridge Commentary considers the quote from Ge. 26 to be an anachronism, because, as the OP implies, there was no systematic expression of the Law of God at the time:

The observance of legal enactments, ascribed to Abraham, is, strictly speaking, an anachronism. Cf. Deuteronomy 11:1, “Therefore thou shall love the Lord thy God, and keep his charge, and his statutes, and his judgements, and his commandments, always”.

But the Bible does mention specific commandments that Isaac would have known about. These include those given to Noah and Abraham. The Noachic laws mentioned in Gen. 9 include not to take human life and not to eat animal flesh with the blood still in it. Jewish tradition holds that these were among seven laws embedded in every human conscience:

• Not to worship idols.
• Not to curse God.
• Not to commit murder.
• Not to commit adultery or sexual immorality.
• Not to steal
• Not to eat flesh torn from a living animal.
• To establish courts of justice.

Most of these laws may be inferred from God's decree about going "righteousness and justice" in Gen. 18, especially in the context of the contrast to the sin of Sodom. In Abraham's case we may also include the commandment of circumcision. (Genesis 17:10)

Assuming the scripture is not anachronistic, the meaning of in the phrase in Gen. 26:5 certainly has to do to keeping "way of the Lord by doing righteousness and justice." In terms of specifics the text has previously mentioned the commandments given to Noah, plus the covenant of circumcision given to Abraham and his descendants.

What was the Law of God Before Moses and How was It Disseminated?

Before the Law of Moses, there was the natural law which is ascribed on the hearts of all mankind.

St. Paul's Epistle to the Romans is generally considered the Scriptural authority for the Christian idea of natural law as something that was endowed in all men, contrasted with an idea of law as something revealed (for example, the law revealed to Moses by God).

14 Indeed, when Gentiles, who do not have the law, do by nature things required by the law, they are a law for themselves, even though they do not have the law. 15 They show that the requirements of the law are written on their hearts, their consciences also bearing witness, and their thoughts sometimes accusing them and at other times even defending them. - Romans 2:14-15

Various commentators have link this passage to the natural law in the Old Testament.

The intellectual historian A. J. Carlyle has commented on this passage, "There can be little doubt that St Paul's words imply some conception analogous to the 'natural law' in Cicero, a law written in men's hearts, recognized by man's reason, a law distinct from the positive law of any State, or from what St Paul recognized as the revealed law of God. It is in this sense that St Paul's words are taken by the Fathers of the fourth and fifth centuries like St Hilary of Poitiers, St Ambrose, and St Augustine, and there seems no reason to doubt the correctness of their interpretation."

Because of its origins in the Old Testament, early Church Fathers, especially those in the West, saw natural law as part of the natural foundation of Christianity. The most notable among these was Augustine of Hippo, who equated natural law with humanity's prelapsarian state; as such, a life according to unbroken human nature was no longer possible and persons needed instead to seek healing and salvation through the divine law and grace of Jesus Christ. Augustine was also among the earliest to examine the legitimacy of the laws of man, and attempt to define the boundaries of what laws and rights occur naturally based on wisdom and conscience, instead of being arbitrarily imposed by mortals, and if people are obligated to obey laws that are unjust.

The natural law was inherently teleological as well as deontological. For Christians, natural law is how human beings manifest the divine image in their life. This mimicry of God's own life is impossible to accomplish except by means of the power of grace. Thus, whereas deontological systems merely require certain duties be performed, Christianity explicitly states that no one can, in fact, perform any duties if grace is lacking. For Christians, natural law flows not from divine commands, but from the fact that humanity is made in God's image, humanity is empowered by God's grace. Living the natural law is how humanity displays the gifts of life and grace, the gifts of all that is good.

Consequences are in God's hands, consequences are generally not within human control, thus in natural law, actions are judged by three things: (1) the person's intent, (2) the circumstances of the act and (3) the nature of the act. The apparent good or evil consequence resulting from the moral act is not relevant to the act itself. The specific content of the natural law is therefore determined by how each person's acts mirror God's internal life of love. Insofar as one lives the natural law, temporal satisfaction may or may not be attained, but salvation will be attained. The state, in being bound by the natural law, is conceived as an institution whose purpose is to assist in bringing its subjects to true happiness. True happiness derives from living in harmony with the mind of God as an image of the living God.

After the Protestant Reformation, some Protestant denominations maintained parts of the Catholic concept of natural law. The English theologian Richard Hooker from the Church of England adapted Thomistic notions of natural law to Anglicanism five principles: to live, to learn, to reproduce, to worship God, and to live in an ordered society. - Natural Law

In addition to the commands given to Adam and Noah, we have the book of Job. Many believe that Job lived between Abraham and Moses, and that Moses or Joshua wrote that book down. Job is filled with ethical standards and comparisons of righteous and unrighteous behaviors. It alludes to messages from God taught to Job by his elders, as well as concluding with a visit from God. Elihu mentions angels. Eliphaz mentions communications from spirits and dreams.

All this speaks of a milieu in which people sought God’s will and wisdom and passed along what they learned or thought they learned, as much was suspect. By being collected in Job with his words endorsed by God and the friends’ words condemned, we know God was active in spreading and curating what passed for his authoritative commands. Job thus stands as the summit of orally transmitted religion.