Jewish law requires that Jews may not eat certain foods, such as pork, certain seafood, or food without the blood removed, and may not mix dairy and meat products at the same meal. These laws also describe how animals must be slaughtered so as to minimize suffering.
2. Jewish Calendar
Jewish law utilizes both a lunar and solar calendar to set the dates of holidays. The dates of holidays and festivals are determined by a lunar calendar, which is based on the phases of the moon. The time from new moon to new moon is 29 days, 12.75 hours. Jewish months are thus either 29 or 30 days. Because a solar year is 365.25 days and a lunar year is about eleven days shorter (12 times 29.5), adjustments are made to the Jewish calendar to assure that holidays remain within the same season (which themselves are solar-based calculations rather than lunar) every year. A lunar month is inserted as a “leap month” as a part of this adjustment, with a total of seven months being added every 19 years.
The Jewish Sabbath and holidays traditionally begin at sunset the evening before the day the Sabbath or holiday is observed. Thus the Jewish holiday of Rosh Hashanah in 1990 was observed September 21st and 22nd, but began at sunset on September 20th.
3. Sabbath and Festival Observance
The fourth of the ten commandments is “Remember the Sabbath Day and Keep it Holy” (Exodus 20:8). Observant Jews do not perform any work on the Sabbath, which is spent in prayer and religious study. In addition to the Sabbath, Jews both in ancient times and today celebrate holidays and festivals, each of which have their own rituals associated with observance. Among these are:
Rosh Hashanah (New Year):