The Shaloh1 tells us that the parshah of the week is connected to the time of year that it is read. In a regular year (not a leap year), it is very common that the portion of Tzav to be read on Shabbat Hagadol, the Shabbat that precedes Pesach. What is the connection between Tzav and Shabbat Haggadol?

The Miracle

Rabbi Schneur Zalman of Liadi2, author of the famed Shulchan Aruch Harav,3 says, "We call the Shabbat before PesachShabbat Hagadol,’ because a great [gadol] miracle4 happened on it. The Pesach [lamb] was taken on the 10th of the month [of Nissan] ... which was Shabbat ... and the firstborns of Egypt gathered near [the Children of] Israel, and asked them, why are they doing so? They responded that this is a Pesach offering to G‑d, because He will slay the firstborns of Egypt. The firstborns went to their fathers and to Pharaoh, to beseech that they send Israel [from their midst], and they refused. The firstborns made war with them and killed many of them. This is the inner meaning of the verse, ‘To smite Egypt with their firstborns.'5 They established to remember this miracle in all generations on Shabbat and called it Shabbat Hagadol. Why didn't they establish [the remembrance of this miracle] on the 10th of the month, whether it fell on Shabbat or during the week, like they established all holidays? Because, on the 10th of Nissan, Miriam passed away and they established it as a fast day when it occurs during the week..."

So we call it Shabbat Hagadol, the Great Shabbat, because a great miracle occurred.

What Makes It Great?

What was so great about the miracle that we should remember it in every generation? This miracle didn't really help the Jewish people, because even after they had their war the Jewish people were still stuck in Egypt. It wasn't until the death of the firstborn that they were they able to go free.

Miriam passed away 39 years after the miracle of Shabbat Hagadol. Why was the fast that was established on the day of her passing able to push off the remembrance of the miracle?

There were many miracles that happened for the Jewish people over the generations, as we say in the Haggadah, "In every generation, they stand up to destroy us, and G‑d saves us from their hands." Generally, either the enemy was destroyed or they were subdued.

What made this miracle great was that it came from the Egyptians themselves. It came from their own firstborns, the “strength and vigor” of Egypt. They themselves went to their fathers and to Pharaoh and demanded that Israel be released, and even went to war for this. The darkness itself became the light. Our enemies became our advocates.

To take it a step further: A miracle is a change in nature. But in this case, even the nature of Torah was changed. In the Torah system, there are things that are holy, and there are things that are neutral, but with some work we can elevate them to holiness. For example, food is generally neutral, but if you recite a blessing over it and use the energy that it gives you to serve G‑d, that food is elevated to holiness.

Then there are things that are intrinsically unholy, which cannot be elevated. Their entire purpose is for us to avoid them.6 For example, with nonkosher food, there is no way to elevate it.

The Egyptians fell into the category of unholiness that is unable to be transformed. Here, however, they were transformed to do G‑d's will.

This is truly a great miracle, beyond any other. It is therefore called “great;” hence the name Shabbat Hagadol.

The Miriam Connection

This will help us understand the connection between Shabbat Hagadol and Miriam's passing.

Rashi7 asks, "Why is the passing of Miriam near the teaching of the Red Heifer? To tell you that, just as the Parah Adumah atones, so does the passing of the righteous atone." Rabbi Schneur Zalman of Liadi8 explains that this means that "they accomplish salvations in the midst of the land by atoning for the sin of the generation, even for those done intentionally, low and depraved."

Just as the miracle of Shabbat Hagadol changed the unholy and what can't be elevated, so did the passing of Miriam atone for low and depraved sins that couldn’t be elevated. The actual sin becomes a merit, and the darkness itself becomes light.

Pushed Off

Now we understand why the remembrance of the miracle could be pushed off to another day—in this case, Shabbat.

It is similar to when Rosh Hashanah falls on Shabbat, the law is that we don't blow the shofar, because an ignorant person may want to hear the shofar and mistakenly carry it in a public domain, a violation of Shabbat. To protect him from breaking the Shabbat, we are communally barred from listening to the shofar.9

You may ask: Why should we all miss out on the great mitzvah of shofar because of a few common folk who haven’t learned the necessary Shabbat laws? The answer is that we, in fact, don’t miss out on accomplishing this important mitzvah. The spiritual effects of the shofar are actually accomplished by the day of Shabbat itself.10

The same is true about Miriam's passing. Since the essence of the great miracle was that the darkness itself became light, which was personified in the passing of Miriam, it was not truly pushed off. The essential idea is accomplished by commemorating Miriam's passing.

The Parshah Connection

At the end of parshat Tzav,11 we read about the seven days of milu'im, a time of induction for Aaron and his sons in the Mishkan service. Why was it called milu'im? Rabbi Schneur Zalman of Liadi12 explains that it comes from the word miluy, which means “full” or “complete.” Regarding the time of Moshiach it says, "That the light of the moon will be like the light of the sun."13 That which was lacking in the moon will be filled. A similar thing happened spiritually, when the Mishkan was set up during that week—the spiritual attribute of malchut (kingship) was raised up.

The moon doesn't give its own light, but merely reflects the light it receives from the sun. When Moshiach comes, however, its status will be raised and it will give its own light. The same thing applies to the spiritual attribute of malchut. Right now it has nothing of its own to give. It only reflects what it receives from the other attributes. However, when Moshiach comes, it will be raised and have what to give on its own. In a small way, this happened when the Mishkan was set up.

In other words, that which is normally dark and doesn't give its own light, the moon and malchut, will begin to give their own light. The darkness itself becomes light.

This idea is seen in the name of the parshah, Tzav. In the Talmud14 it says, that whenever it says Tzav, it is referring to idol worship. At the same time, the Torat Kohanim15 tells us about the word Tzav, that it means, "alacrity [to fulfill G‑d's will], now and for generations, even if it means taking a loss." And Tzav (96) has the numerical value of the two names of G‑d—E-l (31) and Adnai (65)—combined. What is dark is itself giving light.

We can accomplish turning the darkness itself into light through repentance, teshuvah, when our worst sins become merits.16

The common denominator between Shabbat Hagadol, Miriam's passing, and parshat Tzav is that the darkness itself becomes light.17

May we merit the coming of Moshiach soon, when we will see how the darkness and the suffering of the exile will become light. The time has come.