Counting of The Omer

In Judaism, the 49 days between Pesach (Passover) and Shavuot (Feast of Tabernacles) are counted ceremoniously as a commemoration of the Omer ceremony which was celebrated in the Temple in Jerusalem. This process is called Counting of The Omer (English: Sefirat Ha'omer, Hebrew: ספירת העומר).

Source

The source for this tradition is Leviticus 23:15-16:

"And from the day on which you bring the sheaf of elevation offering—the day after the sabbath—you shall count off seven weeks. They must be complete: you must count until the day after the seventh week—then you shall bring an offering of new grain to the Lord."

- The New JPS Translation

Background

The barley harvest in Israel begins during Passover; the omer is a Biblical measure of volume of grain. An omer offering was brought to the Temple on the second day of Passover and was the signal for the allowance of "chadash" (new harvest) grains.

The count

Every night of the counting, a blessing is spoken and the count is stated in terms of both total days and weeks and days. For example, on the twenty-third day the count would be stated thus: "Today is twenty-three days, which is three weeks and two days of the Omer."

As a period of mourning

This period is a time of partial mourning, during which weddings, parties, and dinners with dancing are not conducted, in memory of a plague during the lifetime of Rabbi Akiva, which ultimately killed many of his students. Haircuts during this time are also forbidden.

The 33rd day of the Omer (the eighteenth of Iyar) is a minor holiday commemorating a break in the plague. The holiday is known as Lag B'Omer. The mourning practices of the omer period are lifted on that date, although some communities begin the mourning practices later and resume the mourning after Lag Ba'Omer until Shavuot.

The word "Lag" is not really a word. In ancient Hebrew, letters were used for numerals, and the number 33 was therefore written with the letters "lamed" (L, value 30) and "gimel" (G, value 3), making up "Lag" (33).

Jewish holidays |- |align=center| Shabbat | Rosh Hashanah | Fast of Gedalia | Yom Kippur | Sukkot, Hoshanah rabbah and Shmini Atzeret | Simchat Torah | Chanukah | Tenth of Tevet | Tu B'shevat | Fast of Esther and Purim | Passover | Lag B'Omer | Shavuot | 17th of Tammuz | Tisha B'Av | Tu B'Av |- |align=center|National holidays of Israel |- |align=center| Yom HaShoah | Yom HaZikaron | Yom Ha'atzma'ut | Yom Yerushalayim |}