Bo | What is the significance of the Jewish Calendar?
Updated: Mar 9
In this week’s Torah portion, we read of two special mitzvot given to the Jewish people while we were still enslaved in Egypt. One is Rosh Chodesh, the mitzvah of blessing the new moon. The other is the establishment of the Jewish calendar, with the month of Nisan at the start of it. What is the significance of these mitzvot? Why were they given to the Jewish people before the rest of the Torah? And what are the lessons they teach us about the nature of our relationship with our Creator?
What is the significance of the Jewish calendar?
In the depths of slavery, a message comes to the people. A message from G-d about the future. A precursor to our freedom. The message takes the form of two key mitzvot given to the Jewish people long before we receive the Torah at Mount Sinai.
These mitzvot relate to the Jewish calendar. The first is the mitzvah of Rosh Chodesh. G-d says to Moses and Aaron: "This renewal of the moon shall be the beginning of the months for you. It shall be the first of the months of the year for you.” (Shemot 12:2)
G-d establishes the new moon as the beginning of the month. We know that the moon operates on a 29- or 30-day cycle. Starting off small with most of it enshrouded in darkness, the moon “grows larger” as the days go by, until it becomes a full moon towards the middle of the month. From there, it begins to diminish in size again, before eventually “disappearing” altogether. When it reappears for the first time, it is the new moon – Rosh Chodesh, the beginning of the new month.
Related to this mitzvah of Rosh Chodesh is another mitzvah more implicit in the verse: establishing that month, the month of Nisan – the month of liberation from Egypt – as the beginning of the calendar, “the first month of your year”.
A timeframe for all time
What is the significance of these two mitzvot? On a very basic level, G-d was framing the time for the Jewish people. He says to Moses and Aaron, today is the beginning of the month; on the 10th of this month, each household will set aside a lamb; and on the 14th of the month they will slaughter that lamb and dab its blood on the doorposts. G-d was giving them a frame of reference for what to do and when exactly to do it. We know how important this was because when the angel of death swept through the land of Egypt, he passed over all the houses that had blood on the doorpost, and that night – 15 Nisan – the Jewish people were liberated from Egypt, as we relate each year when we tell the story of Pesach.
What happened to the Jewish people in that generation affects us to this day. Today, we celebrate each Pesach on 15 Nisan – the anniversary of the Exodus from Egypt. G-d established the Jewish calendar at this point in our history, which framed events for all time.
Jewish history is about to begin. Of course, it began with Abraham, Isaac and Jacob, our forefathers, but that relates to Jewish history in terms of individuals. What begins on the night of 15 Nisan relates to national Jewish history. We see G-d intervening on the stage of history to liberate an entire people. And we need a calendar to mark the beginning of that history. Hence the mitzvah of the Jewish calendar, which begins in this week’s parsha.
Why is this month different from all other months?
Why was Nisan chosen as the first month? The Ramban, Rabbi Moshe ben Nachman, explains that this is the month of the great miracles that accompanied the Exodus from Egypt, and that designating Nisan as the first month is an acknowledgment of the seminal importance of these miracles in Jewish history. The Ramban points out that in classic Torah Hebrew, there are no names for the months – they are only numbered in their relation to the first month, the month of our liberation. Similarly, there are no names in Hebrew for the days of the week, which are simply sequenced in their relation to Shabbos. We have Yom Rishon, “the first day” (from Shabbos); Yom Sheini, “the second day” (from Shabbos), and so on. We count from Shabbos and we count towards Shabbos. Shabbos is the focal point of the week.
Says the Ramban, the days of the week are numbered in accordance with the importance of Shabbos, and the months of the years are numbered in accordance with the importance of the liberation from Egypt. Of course, we do also have actual names for the Hebrew months. Besides Nisan, we have Shevat, Tevet, Cheshvan, etc. However, these names only emerged later, after the Babylonian exile, as a reminder of the great miracles that accompanied our liberation from that exile.
In his commentary, Oznaim LaTorah, the great Lithuanian commentator, Rav Zalman Sorotzkin, offers another interpretation for the significance of Nisan becoming the first month. We know that Nisan isn’t the only “first month” of the Jewish calendar. Tishrei, the month we celebrate Rosh Hashanah, also marks the beginning of the year. Put differently, Nisan marks the beginning of the months, whereas Tishrei marks the beginning of the year. What happened to shift the focus of the beginning from Tishrei to Nisan?
Tishrei, we know, commemorates the physical creation of this world – a world made up of inorganic matter, plants, animals and human beings. A world that included the human soul, but nevertheless a world without Torah. The Torah only comes into the world after the Jewish people are liberated from Egypt. G-d guides them directly from Egypt to Mount Sinai to receive the Torah. And from then, the world can fulfil its ultimate purpose – because a world without Torah is devoid of that purpose. Indeed, the reason the world was created was to bring the Torah into it. We see now why Nisan superseded Tishrei as the focus of beginnings. With the liberation of the Jewish people from Egypt, history is really beginning, because this leads us to the giving of the Torah at Mount Sinai. And it’s at this point that the world can begin to achieve its ultimate purpose.
The gift of time
So the Jewish calendar is a lunar calendar as established in this week’s parsha. Because lunar months are 29 or 30 days in length, a lunar year of 12 months is about 11 days shorter than a solar year. To bring it into sync with the solar calendar, and therefore with the seasons of the year, we add in an extra month every two or three years, in accordance with our Oral Tradition. In this way, we don’t lose track of the seasons.
In our hands
The sages of the Talmud, who were among the greatest astronomers of their day, knew exactly when the new moon was going to reappear – yet they waited for two witnesses to come to Jerusalem to testify that they saw it. This system was unsustainable when the exile came, at which point the sages set up a fixed calendar for all future generations. But until that time, nobody knew in advance which day was going to be Rosh Chodesh; the mitzvah was to wait for the witnesses. And, in fact, the Sanhedrin – the supreme court of the Jewish people – even had the authority to move Rosh Chodesh by a day at their own discretion if they deemed it necessary.
What’s the message here? Why wait for the witnesses when they knew when the moon was to appear? Why did the rabbis have the discretion to move Rosh Chodesh? Rabbi Samson Raphael Hirsch, the great 19th century German Jewish philosopher, says that Rosh Chodesh is a time of meeting with G-d. We also know that the date of Rosh Chodesh determines when each of our festivals occur. Pesach occurs on 15 Nisan, Shavuot on 6 Sivan, and so on. And these are times when we meet with G-d. The Hebrew word for festivals is moadim, which comes from the Hebrew word va’ad, which means “to meet”. Says Rabbi Hirsch, when we meet with G-d it must be a choice that we make, rather than a forced meeting determined by the mechanical laws of nature. By being part of the process of setting up that meeting, we are in a sense initiating it. And so the renewal of the moon becomes a sign that we need to renew our connection with G-d, and that it must also happen as a result of our own initiative. That’s why the Sanhedrin had that discretion, and why the setting up of a fixed calendar was not the ideal.
Rabbi Hirsch says the reason why this mitzvah had to be given to the Jewish people while they were still in Egypt was because it was a call to the entire nation that now was the time for spiritual renewal. One of the key teachings of the Torah is our capacity for renewal. We are not subjugated to the laws of nature. We can rise above our own instincts, our own nature. We can make ourselves into the people we were meant to be and live lives of greatness, and it’s in our hands to do that. Like G-d, Himself, who created the world from nothing, we too have the power to generate newness. And that power to transcend our circumstances comes directly from our Creator.
The Jewish calendar embodies this idea of renewal because it calls on us to renew ourselves every month. We don’t live our lives in cycles of years and decades. We live our lives in cycles of months, with the opportunity to renew ourselves every 29 or 30 days. This is what Rosh Chodesh means. The word for “month”, chodesh, comes from the word, chadash, which means “new”. This was G-d’s message to the people enslaved in Egypt – that they had the freedom to renew themselves and achieve spiritual and moral greatness with the Torah’s guidance, renewing not just themselves, but the world in which they lived.
Partners in creation
There is another idea here. We see that this mitzvah of Rosh Chodesh was really setting the tone for the entire relationship that G-d has with the Jewish people. And what is that relationship all about? In the words of the Gemara, we are called on to be “a partner with G-d in the creation of this world”. This mitzvah that we are given right at the outset exemplifies that partnership. G-d says the Jewish calendar will not be determined by Him alone and by the laws of nature He has created; rather, the calendar will be forged as a partnership between G-d and the Jewish people. When the Sanhedrin declares that it is Rosh Chodesh, the new month, then that’s what it is. They have the discretion to move it, and even to add a month to the calendar, thereby determining when the festivals fall, and infusing those days with holiness.
Rosh Chodesh is a reminder to us that our relationship with G-d is based on partnership. It’s for this reason, also, that G-d asked us to put the blood on the doorposts. It’s as if He was saying to us: “You want to be redeemed from Egypt? Become active in this redemption.” We weren’t just passively freed from Egypt by G-d’s miracles; we made ourselves worthy of the redemption by slaughtering the gods of the Egyptians – the lambs – and sprinkling their blood on the doorposts as a bold declaration to the Egyptians: that we are loyal to G-d and His Torah.
To live a G-dly life is to be His partner in making this world a better place. And that is why G-d predicated the journey of the Jewish people and their liberation from Egypt on this mitzvah of the new month, this representation of renewal, this declaration of Divine partnership.