It’s widely accepted amongst biblical scholars that Deuteronomy, the fifth book of the Pentateuch/Torah, was written substantially later than the preceding four books. Probably sometime in the late monarchical period. If that’s true, then it wasn’t written by Moses.
Ultimately we can never go back in time and prove who exactly wrote, edited and redacted this text. However, if it was written sometime between Hezekiah’s reign and Josiah’s reign, maybe only finalised in Josiah’s time, then that would explain a lot of other things in Deuteronomy and the rest of the Old Testament.
In this post, I set out some of textual evidence that supports late authorship.
The opening verse tells us that Moses didn’t write the book
As Peter Enns observes, the opening words of Deuteronomy are “These are the words Moses spoke to all Israel beyond [on the other side of] the Jordan.”
The Jordan River runs north to south. After wandering in the desert, the Israelites approached the Jordan from the East. They then crossed the Jordan to enter Canaan on the West. When the author writes about what Moses said “beyond” or “on the other side of” the Jordan, they mean the eastern side of the Jordan. Because Moses never crossed the Jordan River to enter Canaan (Numbers 20:7-13).
This also means the author is explicitly telling us that they are not Moses.
But could Deuteronomy be recounting Moses’ words?
What if the book wasn’t written by Moses, but was still compiling words that Moses actually spoke?
We should bear in mind that it was a long-standing Jewish literary custom to ascribe writings to an earlier author. Isaiah’s writings cover periods that span well over a century. Maybe he was predicting the future; more likely other people also wrote prophecies and attributed them to his name. Similarly, the last six chapters of Daniel are written in a style that dates after Daniel’s time.
Whoever wrote and compiled Deuteronomy wanted the book to carry Moses’ authority. That could have been because Moses actually said these words and the scribes only bothered to write them down after the Israelites entered Canaan. But it’s also plausible that someone composed a new work that drew on what Moses had previously written. Because that was a thing people did back then.
Plus, there are clues within the text that indicate it was written by someone else — or indeed many other people. When you see all these clues together, you begin to think that Moses couldn’t have written significant portions of Deuteronomy.
In a nutshell, why do scholars think Deuteronomy was written long after Moses’ time?
OK, I read what I’m about to explain here in a book by Alexander Rofé: Deuteronomy: Issues and Interpretation (Edinburgh: T&T Clark Ltd, 2002). It’s all in Chapter 1: The Book of Deuteronomy: A Summary.
The argument goes like this:
Of the five books of law, only Deuteronomy commands that worship has to be in one place; scholars call this the “unification of the cult”. There were only two times in Israel’s pre-exilic history where the cult was unified – during Hezekiah’s reign and Josiah’s reign. Both are after Moses’ time.
So, any writings that assume altar worship could only happen in Jerusalem have to be at least after Hezekiah’s time.
However, when Josiah unified the cult, he’d discovered a book of law in the Temple commanding it; we can therefore deduce that the laws about unifying the cult, which we only find in Deuteronomy, were written between the time of Hezekiah and Josiah. Or during Josiah’s reign.
This was a hypothesis put forward by De Wett in 1805. And it fits.
In more detail – how the ‘unification of the cult’ in Deuteronomy points to it being written later
Deuteronomy 12:1–14 is explicit that no one should build any altars anywhere except in the place that God would later indicate. See vv13–14:
Make sure you do not offer burnt offerings in any place you wish, for you may do so only in the place the Lord chooses
The “place the Lord chooses” refers to the temple in Jerusalem.
It could be that Moses foresaw that the temple would be built. Certainly, that’s the idea that allows the author of Deuteronomy to attribute the text to Moses. If Moses was prophesying, then of course he could refer events that hadn’t happened yet.
The thing is though, if Moses had been prophesying, and if Deuteronomy had been written during or shortly after his time, then people would have known about his prophesy. They would have known that worship anywhere outside the place God would choose was prohibited.
But this is not what we see in the rest of the Old Testament.
Gideon and Elijah both built altars and no one objected (Judges 6:24, 1 Kings 18:30). No one said, “But Moses commanded that you only do that in Jerusalem!” (And the temple had definitely been built by Elijah’s time.)
In contrast, destruction of altars was considered a grave sin in 1 Kings 19:10-14.
There can only be one logical reason for all this: Deuteronomy’s laws about unifying the cult hadn’t been written.
Laws about the judiciary and warfare – more evidence for why Deuteronomy was written later than Moses
The laws regarding the judiciary point to Deuteronomy being composed later; Deuteronomy 16:18-20 and Deuteronomy 17:8-13 contain laws that introduce appointed officials to replace local elders as judges/adjudicators. Again, this points to the book being written much later than Moses.
The laws on warfare in Deuteronomy 20:10–18 also don’t make sense if they were all written by the same person. If you’re in any way familiar with the book of Joshua, you’ll know that the story goes that the Israelites were commanded to wipe out all the inhabitants of Canaan.
The idea that God would command genocide is, understandably I think, one of the big reasons people give when they say they don’t like the Bible. I don’t want to talk about the Canaanite genocide in this post. (If you’re curious, see this footnote: .) For now, all you need to know is that it was a thing in the Old Testament.
If Moses wanted to write a law that said, “You will kill every man, woman, child and animal when you lay siege to a Canaanite city,” then he would have said that. Thing is, he didn’t.
Instead, Deuteronomy says that when the Israelites lay siege to a city, they should first offer terms of surrender. Then, having got to the end of this law, there’s a sentence that effectively says, “Oh actually, that only applies to cities that are far away.” Then, in verses 16–18 there is another law for cities nearby (i.e. Canaanite cities); for these, the Israelites are to kill every man, woman, child and animal (literally: “any breath”).
The text only makes sense if the second law was added at a later date. If Moses had written it in a single sitting, he wouldn’t have structured the law like this.
Oh, and the reason Deuteronomy gives for why the Israelites should kill every living thing in the Canaanite cities is this:
so that they cannot teach you all the abhorrent ways they worship their gods, causing you to sin against the Lord your God.
As any biblical scholar worth their salt will tell you, that was a cause close to Josiah’s heart. This points to late authorship.
Other things that make sense if Deuteronomy was written late
The examples I’ve given so far are from Alexander Rofé’s work. But there are plenty of other implications if Deuteronomy was a collection of laws and writings compiled and redacted at a time later than Moses.
Rizpah and David
Of the five books of law (the Pentateuch), only Deuteronomy forbids the execution of children for the sins of their parents. It’s also the only one that prohibits leaving out executed bodies overnight. The relevant laws are in Deuteronomy 21:22–23 and Deuteronomy 24:16.
So when David executed seven male descendants of Saul for crimes that Saul committed against the Gibeonites (2 Samuel 21), and left their bodies exposed to the elements, either he was completely ignoring what Moses said, or the law hadn’t been written yet.
I get that David didn’t always do the right thing, but he tried to a lot of the time. And, whilst the author of 2 Samuel seems quite uncomfortable about what David did, there is nothing that suggests he was upending the law of Moses. Remember: David was trying to petition God to end a famine. I seriously doubt he would have executed these men as an exercise of royal prerogative over and against Moses. More likely, he thought his actions were lawful.
And if his actions were lawful, then maybe Rizpah’s actions are a big part of why the law was changed. I wrote more on that here.
Adultery and rape laws in Deuteronomy 22:23–27
I’ll be very brief. These verses have two laws: the first is about a betrothed virgin in the city, and the second about a betrothed virgin in the country. Thing is, Deuteronomy 22:23–24 only makes sense if it was written after, and as a counter-case to, Deuteronomy 22:25–27.
It’s another example of how the text doesn’t make sense if it was written by one person. The details are in this post here, and I draw on the work of Sara Milstein.
If you’ve been taught for a long time that Moses wrote the whole of the Torah, then it can be unsettling to learn that probably, actually he didn’t.
I think the Bible is a magnificent book. That’s why I study it. But having read these points that Rofé and many other scholars have made, I struggle to see how Deuteronomy could possibly have been written (or dictated) by Moses.
Sure, some parts of the book are old. Maybe some of them do date back to his time. But there is strong, dare I say it — biblical — evidence, that suggests large parts of Deuteronomy were not written by Moses.
 See Enns, Peter. How the Bible Actually Works. London: Hodder & Stoughton, 2019, 83.
 If you want further reading on the genocide, I’d recommend Peter Enns’ book The Bible Tells Me So. Rachel Held Evans enjoyed that book and reviewed it here. Joshua Edmund Anderson also liked the book, but disagreed with Enns’ conclusion on the genocide. His review is here and is helpful as it sets out a number of Enns’ arguments. Meanwhile, some of Enns’ thoughts specifically on the genocide are on his Bible for Normal People site, namely here.