Biblical system of witnessing the new moon recreated in Jerusalem, as in time of Sanhedrin

And on your joyous occasions—your fixed festivals and new moon days—you shall sound the trumpets over your burnt offerings and your sacrifices of well-being. They shall be a reminder of you before your God: I, Hashem, am your God.




(the israel bible)

December 6, 2021

4 min read

On Monday night, a remarkable event took place, recreating the declaration of the new month as performed by the Sanhedrin in Temple times. 

Fires on the mountain

On Monday night, torches, referred to as masuot, were set up in a chain from the Mount of Olives, recreating the system that was used in the times of the Temple to announce the sighting of the new moon. The mausuot were lit at the time that it was possible to witness the new moon however no actual sighting was made or reported to the Sanhedrin. Three torches were displayed in approximately ten locations, spreading out from Jerusalem to places as distant as Amona and Mount Tabor.

Rabbi Hillel Weiss, the spokesman for the Sanhedrin, emphasized that reestablishing the Biblical system of witnessing the new moon is important to modern Israel.

“Knowing exactly when the month begins has always been important in Jewish practice because the Torah schedules the Jewish festivals according to the days of the month,” Rabbi Weiss explained. “Since the creation of the world, every seven days has been Shabbat. But God gave us the authority, actually the responsibility, of establishing time by setting the months.”

Families pose in front of the torches on Mt of Olives, Jerusalem (courtesy)

Setting the new month by witnesses is considered by Rashi, a prominent commentator on the Bible, to be the first mitzvah (Biblical commandment) the Nation of Israel received after leaving Egypt. With great spiritual meaning, establishing the calendar is far more than a convenience. It is so important that it takes precedence over the Sabbath. In Biblical times, witnesses were permitted to break the Sabbath in order to arrive in Jerusalem and stand before the Sanhedrin.

“This was one of the aspects of the Sanhedrin and, therefore, the basis of justice,” Rabbi Weiss said. “It is not arbitrary or treated lightly by simply printing a calendar and forgetting it. Commanding the Sanhedrin to set the month is as if they have the power to move the moon. Justice is to establish reality. Of course, God created the world. But we are required to establish justice in the world, making us a partner in creation.”

“In the secular world, science establishes reality. By setting the month, the Sanhedrin is acknowledging that there is a higher power above science. It is not enough to calculate the month.”

The calendar system

The lunar cycle lasts approximately 29½ days. Since a Hebrew month needs to consist of complete days, a month is sometimes twenty-nine days long (such a month is known as chaser, “missing”), and sometimes thirty (malei, “full”). The first day of the month, as well as the thirtieth day of a malei month, is called Rosh Chodesh. In the Temples, the new month was a festival, marked by the blowing of the shofar and special sacrifices.

In the times of the Temple, the new month would be established by both calculations and by witnesses appearing before the Sanhedrin. On the 30th day of every month, the Sanhedrin would gather in a large courtyard in Jerusalem called Beit Ya’azek. Pairs of witnesses who claimed to have seen the new moon on the previous night would come to give their testimony and be cross-examined.  If the two accounts were corroborated, the evidence was accepted.

The Sanhedrin would then declare the new month to be sanctified (mekudash). 

The following night, messengers were sent out and a series of mountaintop pyres were lit to spread the word to outlying communities. Though it was incredibly efficient for its time, this system caused a delay for the outlying communities outside of Israel. It is for this reason that Jewish communities outside of Israel observe holidays for two days. 

When the Temple was destroyed and the Sanhedrin disbanded, the Hebrew calendar was figured solely according to the astrological calculations and the template established by Hillel II. It is remarkable that Hillel II’s calculations stood for as long as they did. However, 1,700 years later, there are discrepancies between his calendar and the astronomical reality. As a result, the true date of the appearance of the moon no longer synchronizes with the beginning of the month as it appears on the calendar

On a technical level, the event was a step in the process of correcting the Hebrew calendar. By Biblical law, the new month for the Hebrew calendar was established by reliable witnesses appearing before the Sanhedrin. Hillel II, president of the Sanhedrin in the fourth century, established a written calendar based on astronomical calculations. This calendar, still in use, standardized the length of months and the addition of months in leap years over the course of a 19-year cycle, so that the lunar calendar realigns with the solar years.

“The main obstacle to reestablishing the system of the new month is having a Sanhedrin that is accepted as the authority by the nation of Israel,” Rabbi Weiss said. “This will be a major step towards establishing the true return of the Jews to Israel.”

Share this article

Donate today to support Israel’s needy







Default Donation Form

Personal Info

Credit Card Info
This is a secure SSL encrypted payment.

Donation Total: $100.00


Prophecy from the Bible is revealing itself as we speak. Israel365 News is the only media outlet reporting on it.

Sign up to our free daily newsletter today to get all the most important stories directly to your inbox. See how the latest updates in Jerusalem and the world are connected to the prophecies we read in the Bible. .