The very first commandment given to Jews while they were still in Egypt was to create a calendar based on the cycle of the moon: “And G‑d said to Moses … in the land of Egypt … This month is for you, the head of the months; first it is for you among the months of the year.”¹

The Midrash points out that the Hebrew words for “this month” are הַחֹדֶשׁ הַזֶה, lit., “this renewal.” In other words, G‑d showed Moses the moon in its time of renewal and said to him, “When the moon renews itself, you will have a new month.”²

However, it should be noted that the Jewish calendar is actually a luni-solar calendar.

Although the months of the year follow the lunar cycle, we are commanded to keep the holidays in their proper seasons. If we were to only go by the lunar cycle (as some cultures do), we would have a problem. The solar cycle is approximately 365 days, while the lunar year is approximately 354 days, so the lunar calendar would fall behind the solar calendar by 11 days each year, throwing off the holidays. For example, the holiday of Passover, which is meant to be celebrated in the spring, would eventually fall out in the winter.

To align our lunar calendar with the solar cycle and keep the holidays in the right seasons, we add a thirteenth month every few years to make a “leap year.” Thus, technically the Jewish calendar is considered a luni-solar calendar.

Having said that, we can now return to the question of why we mostly follow the lunar calendar.

Waxes and Wanes

Our sages tell us that the Jews count based on the moon and are compared to the moon.³

Unlike the sun, which gives off a steady and unchanging light, the moon waxes and wanes in cycles. So, too, throughout history we Jews wax and wane. We were redeemed from Egypt and received the Torah, but then sinned with the Golden Calf and the twelve spies. We entered the Land of Israel and built the Holy Temple, but it was destroyed and we went into exile. We rebuilt the Temple, only for it to be destroyed again. During the long exile itself, our standing has waxed and waned. The lesson is that whenever our life feels dark, we know that ultimately it will brighten up again, just like the moon.⁴

But there is a much deeper connection to the moon.

Humble and Majestic

The mystics compare the moon to the divine attribute of malchut (“royalty”). Somewhat counterintuitively, malchut is considered the last of the 10 attributes. Just as the spiritual “light” of malchut is only attained through humbling and nullifying itself to receive from the sefirot above it, so too the moon’s light is only a reflection of the light of the sun.

In a similar way, we are able to become a vessel for the divine light through humbling ourselves.

Adopted from the class of Rabbi Eli Mansour