Answer
The book of Leviticus is about the holiness of God, the sinfulness of people, and the sacrifices and offerings that enabled ancient Israelites to be in fellowship with God. Although there is less narrative content in Leviticus and more descriptions of ritual laws compared to the other books Moses wrote—Genesis, Exodus, Numbers, and Deuteronomy—there is ample evidence regarding the time of its composition. Namely, Moses wrote Leviticus after the Israelites left Mount Sinai, between 1440 and 1400 BC during the 40 years they wandered in the wilderness before entering the Promised Land.
This period marks an important part of Israel’s story. After God freed the Israelites from slavery in Egypt, they traveled to Mount Sinai. The setting of all 27 chapters of Leviticus takes place at the base of Mount Sinai during an 11-month period around 1440 BC. One of the purposes of Israel’s exodus from Egypt was to enable them to worship God freely (Exodus 7:16), and Leviticus details on how they were to do so.
The date 1440 BC is derived from references found in the books that come before and after Leviticus, specifically Exodus and Numbers. Exodus dates Israel’s arrival at Mount Sinai to the first day of the third month after leaving Egypt (Exodus 19:1–2). Later, Numbers records Israel’s departure from Mount Sinai as the twentieth day of the second month of the second year after leaving Egypt—that is, 11 months after they established camp (Numbers 10:11–12).
Additional evidence for when Moses wrote Leviticus is found within the book itself. A key piece of evidence is the last verse of the book: “These are the commands the Lord gave Moses at Mount Sinai for the Israelites” (Leviticus 27:34). This summary statement is supported by other instances throughout the book that mention God giving revelation to Moses (Leviticus 7:38; 25:1; 26:46). Moreover, some scholars have noted that Leviticus includes over fifty references to God directly communicating with Moses.
Yet another clue for when Moses wrote Leviticus is found in Exodus, which reveals that Moses was 80 years old when God freed Israel from Egyptian captivity (Exodus 7:7). Since Moses lived between 1520 and 1400 BC, and the Israelites’ encampment at Mount Sinai occurred approximately 40 years before his death, Moses wrote Leviticus sometime between 1440 and 1400 BC.
The most common argument against Moses writing Leviticus between 1440 and 1400 BC originated in the 19th century among certain European scholars whose theology consisted of denying fundamental doctrines of biblical Christianity such as the inspiration of the Bible, the deity of Jesus Christ, His atoning death on the cross, and His physical resurrection from the dead. The proposal of these liberal scholars, called the documentary hypothesis, is that an unnamed author wrote Leviticus in the mid-sixth century BC—900 years after Moses lived. According to their theory, an unknown priest wrote most of Leviticus and edited portions of Genesis, Exodus, Numbers, and Deuteronomy.
In summary, a straightforward reading of the Bible reveals that Moses wrote Leviticus between 1440 and 1400 BC. Alternative proposals rely on suggestions that originate outside of the Bible and assume that the historical details of Scripture are unreliable.
