Unlike the first four books of the Pentateuch, the Book of Deuteronomy is, for the most part, the Word of G‑d given in the language and style of Moses. Five weeks before his death, Moses assembled the people of Israel in Moab and gave them a parting speech, which formed the core of this book. One of the first things Moses did was reiterate the Ten Commandments, along with other tenets of Judaism.

In a strange twist, there are some significant differences between the original text in Exodus1 and the repeat recorded in Deuteronomy.2

Some of the More Significant Differences

Fourth Commandment:

Exodus Deuteronomy
Remember the Sabbath day . . . you shall perform no labor, neither you, your son, your daughter, your manservant, your maidservant, your beast, nor your stranger who is in your cities. For [in] six days the L-rd made the heaven and the earth, the sea and all that is in them, and He rested on the seventh day. Therefore, the L-rd blessed the Sabbath day and sanctified it.3 Keep the Sabbath day . . . you shall perform no labor, neither you, your son, your daughter, your manservant, your maidservant, your ox, your donkey, any of your livestock, nor the stranger who is within your cities, in order that your manservant and your maidservant may rest like you. And you shall remember that you were a slave in the land of Egypt, and that the L-rd your G‑d took you out from there with a strong hand and with an outstretched arm; therefore, the L-rd, your G‑d, commanded you to observe the Sabbath day.4

Fifth Commandment:

Exodus Deuteronomy
Honor your father and your mother, in order that your days be lengthened on the land that the L-rd, your G‑d, is giving you.5 Honor your father and your mother as the L-rd your G‑d commanded you, in order that your days be lengthened, and that it may go well with you on the land that the L-rd, your G‑d, is giving you.6

Tenth Commandment:

Exodus Deuteronomy
You shall not covet your neighbor's house. You shall not covet your neighbor's wife, his manservant, his maidservant, his ox, his donkey,  or anything that belongs to your neighbor.7 And you shall not covet your neighbor's wife, nor shall you desire your neighbor's house, his field, his manservant, his maidservant, his ox, his donkey, or anything that belongs to your neighbor.8

Why the Differences Matter

It should be stressed that this isn't just an issue of semantics. Some of these differences have practical ramifications. For example, the commandment to “remember” the Shabbat (Exodus) tells us to verbally sanctify the Shabbat through reciting kiddush, etc., while the commandment to “keep” the Shabbat (Deuteronomy) is about refraining from doing forbidden work.

Another example is that in the last commandment, the Exodus version only warns not to “covet” something that belongs to someone else. Conversely, the Deuteronomy version seems to have a new commandment: "You shall not desire." The difference is substantial. "You shall not covet" tells us not to act toward obtaining the object of our desire. "You shall not desire," on the other hand, means that we may not even actively think about it. (More on that in this essay: Do Not Covet.)

This raises the question, if Moses was faithfully repeating what G‑d had said 40 years earlier, then why the difference between the version in Exodus and Deuteronomy?

To be sure, we find specific explanations for some of the differences. For example, the Talmud and Midrash relate that the parallel commands to “remember” and “keep” Shabbat were actually both said by G‑d and miraculously heard simultaneously.9 For whatever reason, “remember” was recorded in Exodus and “keep” was recorded in Deuteronomy.

But what are we to make of all the other differences? Is there an overarching explanation for all them?

Two Tablets

According to one tradition in the Midrash, the two versions correspond to the two sets of Tablets. The version in Exodus was what was written on the first set of Tablets, which were ultimately broken after the Jews sinned with the Golden Calf. The Deuteronomy repeat records what was written on the second Tablets that G‑d gave Moses.10

However, on a literal level, it seems that the verses in both Exodus and Deuteronomy recount what G‑d said at Sinai. So how could both versions be true?

Nations of the World

Rabbi Shlomo Ephraim Luntschitz offers a novel explanation based on the Midrashic tradition that before the giving of the Torah, G‑d first offered the Torah to all the nations of the world, but they rejected it. Thus, the version in Exodus is what the Torah would have looked like had all the nations wished to accept it, and the version in Deuteronomy is for the Jews alone. Thus, the first version only speaks about sanctifying the Shabbat, but not about the prohibitions. This also explains why the creation of the world is given as the reason for Shabbat in the first version, but the Exodus (a uniquely Jewish experience) is recorded in the second version, in Deuteronomy. Also, since the first version is more universal, it only prohibits acting toward obtaining another’s belongings, but doesn’t require the higher standard of not even desiring it, as does the Deuteronomy version.11

Ultimately, among other difficulties, this explanation has the same issue as the Midrash’s explanation: both versions seem to be referring to the same event at Sinai.

G‑d’s Words and Moses’ Words

Commentaries explain that the difference can be understood by taking into account the most obvious difference between the first four books of the Torah and Deuteronomy. As we explained above, Deuteronomy is Moses' own narrative of what had occurred. Thus, the Exodus version is how G‑d himself said it, while Deuteronomy tells how Moses recounted it.12

(This explains why the second version has additions like this one in the Sixth Commandment: “as the L‑rd your G‑d commanded you.” Obviously, G‑d didn’t say those words when he spoke at Sinai, but when Moses retold the story, such insertions were natural.)

Of course, like the rest of the Torah, Moses communicated Deuteronomy as a prophet of G‑d. It contains not his own ideas, but the faithful, prophetic transmission of G‑d's message. But in this case, the message is expressed through the mind and words of Moses, making it more readily understood to our minds as well.

Why The Need for Two Versions

The Lubavitcher Rebbe explains that the reason for this difference goes to the very heart of what happened when G‑d gave the Torah at Mount Sinai.13

There are two aspects of the Torah. On the one hand, it is G‑d’s beloved treasure, His intimate wisdom, and ultimately it is “one with Him.” But then G‑d takes that wisdom and applies it to matters of our world, thereby investing something of His very self into a way of thinking that is accessible to human beings. This is the Torah as G‑d gave it to us here in this physical world, where we must study and delve into the Torah with our own understanding, assimilating its approach and using its wisdom and laws to transform the world into a sacred space.

So G‑d didn’t simply present us with a set of instructions. G‑d chose to invest His wisdom and will in the Torah and to entrust the human mind with the task of deducing and comprehending the divine teachings and commandments it contains. This way, we aren't just receiving His wisdom in the abstract. Rather, the Torah itself becomes part of our own intellect, our very selves. In studying this divine wisdom, then, we are paradoxically connecting and integrating the infinite with the finite.

So, on the one hand, the student of Torah must ask all the questions that come to mind and not fear any of them—no matter how uncomfortable they make him or others feel. He can never allow himself to be satisfied with easy answers, and must even seek out apparent contradictions in an attempt to resolve them. This is how Torah is studied and acquired.

Yet when it comes to fulfilling the Torah in practical terms, the same student must follow the Torah’s instructions with utter confidence that this is G‑d’s absolute will. Indeed, even in his learning of Torah, he must understand that this is a divine wisdom that he can never entirely comprehend, and that the main thing is to bring it into this world of action.

This very crucial and seemingly paradoxical idea—that on the one hand it is divine wisdom and on the other we are tasked to comprehend and understand it with our own limited intellects—is something that we all need to keep in mind when studying the Torah. If we forget that it is divine wisdom, we may decide not to keep those parts we do not understand. If we forget that we are tasked to understand it with our own minds, we will never come to acquire Torah as our own. Therefore it was important that this idea be expressed at the very giving of the Torah with the different versions of the Ten Commandments—one version expressing how G‑d said it, and one how the divine will and wisdom was expressed through the intellect of His faithful prophet Moses, all the while remaining G‑dly and transcendent.