Shalom everyone! Rosh Chodesh, which means “beginning of the month” or “head of the month,” is the name for the first day of every month on the Hebrew Calendar. The event is marked by the birth of a “new moon,” the beginning of a new lunar phase. Rosh Chodesh is considered a minor biblical holiday, similar to the intermediate days of the holidays of Pesach and Sukkoth.
YAH commanded B’nei Yisrael to mark the occasion of Rosh Chodesh each month as a time of recognition. In the Book of Numbers, YAH says to Moshe (Moses):
“Also in the day of your gladness, and in your appointed seasons, and in your new moons, ye shall blow with the trumpets over your burnt-offerings, and over the sacrifices of your peace-offerings; and they shall be to you for a memorial before your God: I am the LORD your God.'” ~ Numbers 10:10
In ancient Israel, the occurrence of Rosh Chodesh was confirmed on the testimony of two independent reliable witnesses observing the new moon. The Sanhedrin would then declare Rosh Chodesh for a full 30-day or a deficient 29-day month, and then communicate the news throughout the Land of Israel and the Diaspora. On the day after the new moon sighting, a festival was held to commemorate the occasion which included a solemn convocation, the sounding of shofars and special sacrificial offerings. Rosh Chodesh was a very significant festival in ancient Israel. The entire calendar depended upon the declarations of Rosh Chodesh; without these declarations, there would be no way of knowing when holidays were supposed to occur.
In later times after the destruction of the Holy Temple in Jerusalem, Rosh Chodesh was mathematically calculated using a fixed calendar. Over time, a custom developed whereby an additional day could be added to a month to ensure that certain holidays, for example Yom Kippur, did not fall on days immediately before or after Shabbat (Sabbath/Seventh Day of the Week).
In modern times, Rosh Chodesh begins the day after the sighting of the new moon at 18:00 hours Jerusalem time. Even though a fixed calendar exists, Rosh Chodesh is still announced in synagogues worldwide on the Shabbat immediately preceding Rosh Chodesh. This Shabbat is referred to as “Shabbat Mevarchim” (“Shabbat of Blessing the New Month”). The announcement of Rosh Chodesh is made after the weekly Torah reading in a special prayer beginning, “May it be Your will… that You renew this month for us for good and for blessing.” The name of the new month and day of the week on which it falls are announced during this prayer. Rosh Chodesh Tishrei is never announced as it coincides with Rosh HaShanah, the Jewish New Year or “Head of the Year.”
In some Jewish communities, women refrain from work on Rosh Chodesh as a reward for the ancient Israelite women’s refusal to participate in the sin of the Golden Calf.