Rosh Chodesh which literally means "Head of the Month" is a monthly holiday that celebrates the arrival of the new moon, marking the start of a new month in the Jewish calendar.
The Jewish Calendar is a lunar calendar with twelve lunar months and 354 days per year. Each lunar month consists of 29 1/2 days. Since it is impossible to switch months in the middle of the day, certain Hebrew months have twenty-nine days whilst others have thirty days.
In order for the Jewish Festivals to be synchronized with the proper season, for example Passover (Pesach) which must fall in the spring (in Israel - the Northern Hemisphere), a leap year is added every few years. In a nineteen year cycle there will be seven leap years.
The Jewish leap year, however, is not like the leap year in the Gregorian calendar which is one day added on at the end of February every four years. A Jewish leap year adds on an entire month to close the gap between the 354 day lunar calendar and the 365 day solar calendar. Since the month of Adar (approximately February-March) is the last month of the Hebrew year, we add on an extra month at this time. We then have Adar I and Adar II which assures us that the holidays will be celebrated in the proper season. Originally, the date of Rosh Chodesh was confirmed on the testimony of witnesses observing the new moon, a procedure known as Kiddush Hachodesh (sanctification of the month). After the Sanhedrin (an assembly of either 23 or 71 elders or rabbi's, appointed to sit as a tribunal in every city in ancient Israel) declared Rosh Chodesh for either a full 30 day month or a 29 day month, news of it would then be communicated throughout Israel and the diaspora.
This system was dependent on the functioning of the Sanhedrin to declare the month, and to communicate this month to far-flung Jewish communities. In the 4th century CE, this became impossible and instead a fixed calendar of 29 and 30 day months was instituted by Hillel.
At the end of a 29 day month, Rosh Chodesh is celebrated for one day, on the first day of the new month. At the end of a 30 day month, Rosh Chodesh is celebrated for two days - the 30th day of the previous month, and the 1st day of the new month.
With the exception of the month of Heshvan, the eighth month of the year, every single month of the Jewish Calendar has some sort of special day or special observance. The importance of Rosh Chodesh is therefore obvious.
The names of the months are not Hebrew but Babylonian. The Bible refers to the Jewish holidays only by the order of the months and not by the Babylonian names which were assigned long after the canonization of the Torah. For example, the Torah gives the date of Yom Kippur as the tenth day of the seventh month, whilst the date of Pesach is the fifteenth day of the first month.
The month of Iyar (אִיָּר), the second month in the Hebrew calendar (counting from Nisan), is a spiritually rich and significant time in the Jewish year. It is uniquely positioned between Pesach and Shavuot, and is entirely encompassed by the Sefirat HaOmer – the 49-day period of personal refinement in preparation for receiving the Torah at Sinai. Iyar is a month dedicated to healing, growth, and spiritual elevation.
The Acronym – "Ani Hashem Rofecha"
The name Iyar is often associated with the acronym "אֲנִי ה' רֹפְאֶךָ" – “I am Hashem your Healer” (Shemot 15:26). This verse was spoken after the Jews left Egypt and arrived at Marah, where bitter waters were miraculously sweetened. Many mefarshim (commentators), including Rashi and the Midrash, highlight that Iyar is a time of spiritual and physical healing. The Arizal teaches that each day of Iyar holds unique healing energy, and Chassidic masters often encouraged special focus on personal refinement during this month.
The Mazal (Zodiac Sign) – Shor (Taurus)
The mazal (zodiac sign) of Iyar is Shor (שׁוֹר) – the Bull. The bull symbolizes physical strength and stubborn potential, which, when properly directed, becomes powerful service of Hashem. According to the Bnei Yissaschar, the strength of Shor corresponds to the work of character refinement during the Omer. Just as a bull must be guided and controlled, so too our physical drives must be refined and sanctified.
The Letter – Vav (ו)
According to the Sefer Yetzirah, each month is connected to a Hebrew letter. Iyar is associated with the letter Vav, which symbolizes connection and continuation. Vav is a connective letter, often meaning "and" in Hebrew. This represents Iyar’s role in linking freedom (Pesach) with revelation (Shavuot). The Arizal explains that Vav also reflects the six days of creation and the ongoing process of rectification (tikkun) through daily effort.
The Tribe – Yissachar
Each month corresponds to one of the Shivtei Yisrael (Twelve Tribes). Iyar is aligned with Yissachar, the tribe known for Torah learning and deep understanding (see Bereishit 49:14-15). The Midrash and Rashi emphasize that Yissachar "bore the yoke" of Torah with joy, and their connection to Iyar reinforces the month’s preparation for Matan Torah. This tribal connection also underscores the focus on introspection and intellectual avodah (spiritual service) during this time.
The Body Part – Right Kidney
In the mystical system of correspondences found in the Sefer Yetzirah and elaborated on by Rabbeinu Bachya and the Arizal, Iyar corresponds to the right kidney, which is associated with counsel and clarity of thought. The Talmud (Berachot 61a) teaches that the kidneys advise a person. Iyar, therefore, is a time to seek divine wisdom and inner guidance as we align our actions with Torah values.
The Precious Stone – Sapphire (Sapir)
The stone associated with Iyar, based on the Choshen (breastplate) of the Kohen Gadol, is the Sapir (סַפִּיר) – sapphire. According to the Zohar and Rabbeinu Bechayei, this stone symbolizes clarity, wisdom, and divine communication. The Tablets (Luchot) were said to be made of sapphire, further linking this stone to Torah and spiritual revelation, fitting for the month that leads into Matan Torah.
Other Highlights of the Month:
• Lag BaOmer (18 Iyar): A deeply mystical day commemorating the passing of Rabbi Shimon bar Yochai, the revealer of the Zohar. According to the Arizal, Lag BaOmer is a day of joyful light amidst the serious tone of the Omer.
• Healing from the Makkot (plagues): The Midrash (Mechilta) states that during Iyar, Hashem began to heal the spiritual wounds of Egypt, preparing Bnei Yisrael to receive the Torah.
• Some Chassidic teachings (especially in Sefat Emet) see Iyar as a time when the hidden light of Torah begins to awaken in the soul, step by step.