Like all other biblical holidays, Rosh Chodesh is not observed today as required by biblical law. This is because of changed social circumstances and because the principle element of the biblical worship was animal sacrifices, which was discontinued after the Romans destroyed the Jewish Second Temple in 70 CE. Additionally, the name of the celebration was changed from “Chodesh” to “Rosh Chodesh,” which in the Torah did not mean “New Moon,” but “First Month” and referred to the month now called Nissan when Passover occurs.
Numbers 28:11 mandates special sacrifices to be brought on every Rosh Chodesh. These consist of a burnt offering of two bullocks and seven he-lambs, a guilt offering of a he-goat, a meal-offering, oil, flour, and wine.
Name of holiday
The Spanish rationalist, Bible commentator, and philosopher Abraham Ibn Ezra and the French mystically-minded Bible commentator Chizkiyah ben Manoach Chazkuni explain that the Bible only calls the first day of the month of Nissan Rosh Chodesh, and that the term Rosh Chodesh means the first of the months, because the Bible considers Nissan the first month of the year. The Bible calls all other first days of the months simply Chodesh, as indicated in Numbers 28:14 and I Samuel 20.
They point out that Numbers 28:14 applies the Nissan sacrifices obligation to the first day of every other month: “This is [also] the burnt offering of every Chodesh throughout the months of the year.”
The name Rosh Chodesh, however, was used in post-biblical days as the name of the first day of every month.
The Italian exegete, philosopher, and physician Obadiah Sforno notes that while the only biblical observance for the new moon was the sacrifices, I Samuel 20 makes it clear that the Israelites added other customs to enhance the celebration. I Samuel 20:19 indicates that the day before Chodesh (the New Moon) was called “the day of work,” thereby indicating that on Chodesh people did not work. Additionally, I Samuel relates that Saul and his court were celebrating the new moon with a feast, and David states that he was attending a family feast. The feast may have been the custom of all Israelites at that time to celebrate Chodesh.
Ehrlich noted additional ways that Chodesh was celebrated by ancient Jewry in his commentary on Numbers 1:1 in his book Mikra Ki-Pheshuto (The Bible According to its Literal Meaning). He sees that Numbers 1:1 begins by stating that God spoke to Moses on the first day of the second month. He suggests that the Torah is reflecting the ancient idea that Chodesh was a day of learning. It was the day that God communicated his message to Moses, and Moses, in turn, gathered the Israelites, who were celebrating Chodesh as a semi-holiday in which they did not work, and Moses taught them what he heard from God. Ehrlich’s view is supported by Deuteronomy 1:3 which also reports that Moses informed the Israelites on the first day of the eleventh month what he heard from God. Also, the prophet Ezekiel spoke to the people on four occasions on Chodesh: 26:1, 29:17, 31:1, and 32:1. Also in II Kings 4:23, we read that the Israelites traveled to prophets on Chodesh to hear God’s words. None of these practices are observed today.
Important items done on this day
Ehrlich notes other significant religious matters done on Chodesh. The tabernacle was constructed on the first day of the first month (Exodus 40:17). The Levites began to sanctify the temple during the reign of King Hezekiah according to II Chronicles 29:17 on Chodesh. God told Ezekiel in II Chronicles 45:18 to sanctify the temple on Chodesh. Ezra began the return from the Babylonian exile on Chodesh of the first month (Ezra 7:9) and arrived in Jerusalem on Chodesh of the fifth month. He may have timed the entry to occur on Chodesh because of the significance of the day. Today Rosh Chodesh is observed by Orthodox and Conservative Jews by saying Hallel, composed primarily with Psalms, and certain prayers, and a reading from the Torah.
Women and the new moon
Many Jewish women consider the new moon as a special day for them and arrange learning sessions around this day. They may have chosen the day of the new moon because the moon cycle resembles the menstrual cycle in some ways. However, it may be that this women’s learning is a recollection of the ancient practice when all Jews used the day to study, a recollection passed on from mother to daughter.