Passover, Sukkot and Purim: the Jewish festivals of the full moon

Anyone who looks at the sky on the nights of the great Jewish festivals almost always notices the same thing: the Moon is full or nearly so. This is no accident. The Hebrew calendar begins the month with the new Moon, and some of the most important festivals fall on the fifteenth day, in the middle of the month, when the lunar disc is fully lit. Night-time light thus accompanies the story of the Exodus, the stay in the booths and the memory of the deliverance told in the Book of Esther.

Passover and the night of the Exodus

The Book of Exodus, in chapter 12, establishes that the month of liberation from Egypt shall be for Israel the first of months. The Passover lamb was slaughtered on the fourteenth of the month, and the feast of Unleavened Bread began that same evening, with the fifteenth. In the oldest texts the month is called Aviv, the month of ears of grain, and in those after the exile Nisan. The link with spring is written into the name itself.

The evening of the seder, the ritual meal that opens Passover, therefore takes place under the spring full moon. This coincidence had consequences for Christianity too: the death and resurrection of Jesus, placed by the Gospels in the days of Passover, tied the Christian feast for ever to that same moon, and calculating the date of Easter became one of the great problems of medieval science.

Sukkot and the month of Tishri

Six months later, on 15 Tishri, Sukkot begins, the feast of booths, prescribed in chapter 23 of Leviticus. For seven days people live, or at least eat, in temporary huts, in memory of the journey through the desert. Here too the full moon, falling in autumn near the equinox, lights the nights of the festival. The month of Tishri had opened with Rosh Hashanah, the New Year, when the Moon was only a thin thread.

In antiquity Sukkot was also a harvest festival, and the Mishnah describes the night ceremonies in the Temple, with great lamps lit in the courtyard and pious men dancing with torches in their hands. According to the same text, there was no courtyard in Jerusalem that was not lit by that light. The autumn full moon was the backdrop to one of the most joyful festivals of the year.

Purim, Tu Bishvat and Tu B'Av

Purim, which recalls the events told in the Book of Esther, is celebrated on 14 Adar, and in cities that were walled in ancient times, such as Jerusalem, on the 15th. In years with two months of Adar it is celebrated in the second, so that it stays one month before Passover. Tu Bishvat, the new year of the trees, also falls on the 15th, of the month of Shevat: the name itself means fifteenth of Shevat, written with the Hebrew letters worth nine and six.

Then there is Tu B'Av, the 15th of the month of Av, remembered by the Mishnah as a day when the young women of Jerusalem went out dressed in white to dance in the vineyards. It is a minor observance, but it confirms a clear tendency: the full moon, in the middle of the month, was the natural moment to gather the community at night, when moonlight made open-air celebrations possible.

The lunar rhythm does not concern only the mid-month festivals. Rosh Chodesh, the start of each month, is marked by special prayers, and in many communities a blessing for the waxing Moon, Kiddush Levanah, is recited outdoors in the days after the new Moon and before the full. The calendar thus becomes a continuous dialogue between human time and the time of the sky.