Rabbi Yisrael Shachor
Former Rosh Kollel in Chicago


The Jewish people define the months according to the moon and they declare the new month when the new moon is first seen.
Who declares the new month?

This is a complicated question and we will divide it into two parts:

1. When the Jews declared the new month by seeing the new moon when the Sanhedrin still existed in Jerusalem.

2. Since we do not declare the new month by first seeing the moon until the Messiah comes.

The Mishna in Sanhedrin 2 says that the declaration of the new month is done by three; there is no need for the seventy-one wise men from the Sanhedrin to do so.


The Rambam in Sefer Hamitzvot, positive commitment 153, writes that the Mitzva of declaring the new month can only be done by the Sanhedrin in Israel. However, the Ramban disagrees with the Rambam and says that any three Rabbis who sit together can declare the new month. Therefore, even when the Sanhedrin of seventyone was canceled and left the Chamber of Hewn Stone, the Jews continued to declare the new month.

This is not the only disagreement between the Rambam and the Ramban regarding this issue. From the Rambam in Sefer Hamitzvot we learn that there was always a Beis Din in Israel who declared the new months, as he writes, “This is a great basis of faith”. The Rambam explains that the known way to calculate the months and the years does not define when the holidays will be celebrated because we do not declare the new month and add another month to the year out side of Israel, the new month can only be declared by the Sanhedrin in Israel.

The Rambam believes that once the Sanhedrin is canceled, the declaration of the new month is also canceled just like the sacrifices were canceled when the first Temple was destroyed. Therefore, Hillel Hasheni defined the calendar, so that the Beis Din in Israel will declare the new month according to the calendar and the Jews abroad will follow their declaration.
However, the Ramban believes that even when the Sanhedrin was canceled, the new month continued to be declared by a Beis Din of three wise men for hundreds of years until they finished writing the Talmud, as long as the Jews lived in Israel.

Now we will return to the words of the Rambam who defined this Mitzva as “a great basis of faith”- what does he mean? The Rambam explains the meaning and says that if there will be a situation in which all the Jews will leave the land of Israel then there will not be a Sanhedrin that can declare the new month and the known calculation will be useless. However, the Rambam quickly adds that there is no need to worry that there will ever be such a situation and he writes: “G-d will never allow this because He promised that the Jewish nation will never be demolished.”

This is the “great basis of faith”, that the declaration of the new month will never stop, and we have a great promise, during the long years of exile there will always be Jews in the land of Israel until the Messiah comes.

This issue must be explained; how does the Rambam know that there is such a promise because as we know, many commandments were canceled during the destruction of the Temple? The Smag writes that since the destruction we are left with only 270 commandments. He learns it from the verse “I am sleeping and my heart is awake”- I am sleeping in exile, and my heart is awake-we have 270 commandments like “Er” (awake). Why does the Rambam see such significance –a great basis of faith- that the declaration of the new month will always exist for the Jewish people, even when they are in exile? We can explain that from the time that Hashem tells Moshe “This month shall be for you the beginning of the months” it is known that the holiness of the Jewish nation and the holiness of the time are connected and it is impossible to disconnect the two. The Rambam tells us a great basis of faith that the holiness of the nation and the holiness of time are both connected to the holiness of the land.

This is also explained by the Chatam Sofer in Masechet Chulin 7according to the Sifri (Yevamot 80) “your forefathers possessed and you shall possess it” (Deuteronomy 30:5) – they have the first and second possession but not the third one. Rashi says that Yehoshua gave the first holiness to the land but it was canceled during the first destruction of the Temple, the second holiness that was given to the land of Israel by Ezra is forever and was not canceled with the destruction of the second Temple and therefore, there is no need to declare the land holly for the third time.

The Rambam explains in Hilchot Beit Habchira 6:16 that the first holiness that was gained by conquering was canceled by the conquering of Nevuchadnezar, but the second declaration of holiness that was done by Ezra was not gained by conquering but by the possession of Jewish people, and therefore, when Titus destroyed the second Temple it did not cancel the holiness. The Chatam Sofer adds that if the possession of the Jews of the land would end, also the holiness of Ezra would be canceled. And he adds that if God forbid there will not be even one Jew left in Israel, and the Jewish nation would be in exile, this would be the destruction of the Jewish nation.

I hope that we will be zoche that the Messiah will come soon and that the Rambam’s words at the end of Hilchot Melachim that all of the laws will return in the days of the Messiah will come true soon.