The early books of Hebrew scripture, Genesis and Exodus in particular, tell the story of the Israelite people’s evolution from a single individual to a large nation. As part of this story, these books also show how the Israelites’ perception of morality shifts over time. Though the basic tenets do not change, the increasingly complex society the Israelites live in requires a correspondingly intricate set of codes and regulations. Morality therefore evolves from a simple recognition that notions of right and wrong are necessary into an elaborate system of rules and duties, one that requires individuals to recognize that they have duties to God, to one another, and to themselves.

The problem of good and evil is present from the outset of Hebrew scripture. In the Book of Genesis, the deity Yahweh forbids Adam and Eve from approaching the Tree of Knowing Good and Evil. Yahweh wants Adam and Eve to remain ignorant of the difference between good and evil because it is that ignorance that maintains the boundary between gods and humans. If Adam and Eve eat from that tree, Yahweh says, they will “become like one of us.” Adam and Eve do eat from the tree, of course, and Yahweh expels them from the paradise of his garden, though not without first making clothes for them from animal skins. This story suggests, then, that humans are different from all other animals because they recognize the importance of morality. Having a conception of right and wrong is a great achievement, but it also comes with a terrible cost, since life is made difficult precisely because we believe that there are good actions we should be undertaking. Life would be easier, perhaps even blissful, if we lacked morality, but we would be little better than animals without it.

Later in Genesis, however, the human accomplishment of morality loses some of its luster as it becomes clear that people are frequently unable to live up to their moral standards. Humans become so wicked, in fact, that Yahweh floods the Earth to rid it of his vile creations, saving only Noah and his family. After doing so, Yahweh announces that he will never do so again, since “the inclination of the human heart is evil.” Yahweh realizes that it is unjust to punish humanity collectively, since he created people with a natural tendency to act badly. Thus Genesis reveals that while morality is a fundamental human characteristic, it is extremely difficult to live a moral life since our instincts run counter to what we believe we ought to do.

The Book of Genesis, however, is very vague about what specific actions our morality should consist of, stipulating only that Adam and Eve should not eat from the tree, that no one should commit murder, and that people should reproduce. These few guidelines may work on a very small scale but they are hardly sufficient to serve as a guide for people living in a large and complex society, so the following books of Exodus and Leviticus make up for this absence by stipulating a series of commandments—613 in total—that govern individual and community affairs. These commandments range from highly specific dictates about proper clothing, food, and herding practices, to general rules forbidding murder, theft, and adultery, and they also stipulate punishments for many of the violations they describe. In Genesis, morality has been a problem in that people have little inclination to be good on their own. Exodus presents a solution to this problem by giving people extremely detailed guidelines to follow and instilling the fear of punishment in humans as a means of encouraging them to behave morally. The growing complexity of moral law reflects the growing complexity of society, which in Exodus encompasses hundreds of thousands of people, rather than the handful of families described in Genesis.

Moreover, the Book of Exodus shows that morality consists of a wide range of duties. This view of morality is made explicit in the Ten Commandments, which depict three different kinds of obligations. The first type of duty is religious, which is embodied in the commandments to cease worshipping other gods, to stop making idols, to refrain from using Yahweh’s name in vain, and to sanctify one day of the week. The commandments then move on to social obligations, requiring the Israelites to honor their parents and forbidding them to murder, commit adultery, steal, or lie. The final kind of duty that the Ten Commandments present is the duty to oneself, which is expressed in the final commandment, the prohibition on coveting. Coveting is an internal action, one that has no negative consequences on other people, but is nevertheless important to avoid as it reflects a level of dissatisfaction with oneself that Exodus presents as problematic. The development of morality across time in Hebrew scripture thus culminates in the recognition that ethical behavior in a complex society is a matter not merely of metaphysical beliefs and social actions, but of self-conception and self-awareness.