Toward the end of Parshat Chukat, the Torah quotes a mysterious source. In Numbers, chapter 21, the narrative describes the Israelites’ travels: after leaving the Zered valley, they camp “on the other side of the Arnon” – a river marking the border between Moab and the Amorites.1 The text then states:

Concerning this, it is told in the Books of the Wars of the L-rd, “[from] Vahev in Sufah, and the valleys of Arnon. And the spilling of the streams that turned to settle at Ar and leaned toward the border of Moab.”2

Leaving aside the obscure nature of these verses, the most obvious question that jumps off the pages is: What is the “Book of the Wars of the L-rd”? Is it perhaps an ancient book that we’ve since lost? Below, we will examine the approaches of several commentators.

1. Not An Actual Book

Rashi and his grandson, Rashbam, explain that the word we typically translate as “book,” ספר, here means “story” or “account.” In his view, the verse isn’t citing an actual lost volume, but saying that when people retell the stories of G‑d’s miraculous battles on Israel’s behalf, this event at Arnon will be included among them, just like the Splitting of the Sea.

2. A Lost Historical Book of Wars

Conversely, Ibn Ezra writes that there was indeed an actual book by this title, now long lost, in which “the wars of the L-rd” were written down for posterity. He even speculates that its origins might date back to the time of Abraham. He notes that many writings from biblical times have been lost (citing examples like Divrei Natan and others mentioned in Tanakh3), and The Book of the Wars of G‑d was likely one of those lost sources.4

Nachmanides further elaborates on how such a book came to be. He explains that in each generation, there were wise men or bards – whom Nachmanides calls “moshlim” (poets) – who recorded the great battles and victories of their times, often in poetic form. The Torah, he says, is quoting a snippet from one such book. 5

3. A Record of Borders and Forbidden Lands

Chizkuni writes that the Israelites kept a book in which they recorded the borders of lands they passed. This log included entries such as this cryptic line, which is essentially a list of locations. According to this, the book served as a geographic and halachic record of their journey, particularly noting where they were forbidden to wage war, referencing the warnings against waging war against Edom, Moab, and Ammon found in Deuteronomy Chapter 2.6

4. Exodus or Deuteronomy

The Targum Yerushalmi renders the Book of the Wars of the L-rd as “the Book of G‑d’s Torah.”7

Which book?

The Midrash Aggadah singles out the Book of Exodus, which recounts G‑d’s war against Egypt and the Splitting of the Sea. It connects this to the verse in Exodus, “Until Your people cross, O L-rd…”8, and explains that this refers both to the crossing of the Arnon Valley and later the crossing of the Jordan. According to this view, the places mentioned in the verses above are all reflections of allusions found in the Song at the Sea, pointing to past and future miracles.9

Rokeach writes that the Book of the Wars of G‑d is a reference to the Book of Deuteronomy, which records how G‑d gave mighty nations into the hands of the weak — for example, the Emim, who were defeated by the Moabites; the Refa’im, defeated by the Ammonites; and the battles against Sichon and Og. All of these victories were miraculous and thus worthy of being called “wars of the L-rd.”10

5. A Book Open Before G‑d

Ohr Hachaim interprets the Book of the Wars of the L-rd as the heavenly record before G‑d. The verse is understood as follows:

In the book that is before G‑d, which concerns the wars and territorial inheritances of the nations. That divine book determines which nation will receive which land. And in that book, it is stated that in the future—at the end (besofah)—this very border will be given to Israel.”11

6. What Will Be Said in the Book

Onkelos translates the verse to mean: “Therefore it will be said in the book – [about] the wars of Hashem…” In his reading, the Book of the Wars of G‑d is not the name of the book, but the subject of what will be said in the book. It will contain accounts of G‑d’s wars — but the title of the book itself is not given.12

This is similar to the explanation of some later scholars who explain that the book was not yet written in the days of Moses. Rather, the Torah is stating that these events will be recorded in the future by the sages and chroniclers who would later write a history of G‑d’s wars.13