("sheaf"). The offering of new barley brought to the
Temple on the second day of
Passover. The Omer measure is one-tenth of an ephah (i.e., 2.2 liters) and therefore a relatively modest offering (see Lev. 23:9ff.), but until the Omer had been brought to the priest in the Temple, none of the new produce could be eaten. The biblical instruction is to bring this harvest offering "on the day after the Sabbath." This led to a bitter controversy between the Pharisaic rabbis and the
Sadducees. The rabbis interpreted the term "Sabbath" in the text to mean the first day of the Passover festival, i.e., the 16th day of the month of Nisan. For the Sadducees, and later also for the Karaites, it meant the weekly Sabbath. Since the Bible goes on to enjoin that "from the day on which you bring the sheaf of the wave offering---the day after the Sabbath---you shall count seven weeks," and that the 50th day shall be the festival of
Shavu'Ot, the Sadducees maintained that Shavu'ot always fell on a Sunday, exactly seven weeks after the Sunday following Passover. Because of this controversy, the rabbis emphasized reaping the new grain on 16 Nisan, even if the day itself happened to be a Sabbath. The procedure was carried out with great ceremonial and public proclamations (
Men. 10:1), and has been revived in agricultural settlements in modern Israel.
With the destruction of the Temple and the cessation of all offerings (see Sacrifices and Offerings), the practice of counting the days between Passover and Shavu'ot survived on rabbinic authority only. From the night of 16 Nisan until the end of the seven-week period, every day is counted separately, the number of days and weeks of the Omer period being mentioned. The counting is done at night during the Evening Service (in accordance with the Babylonian custom; in Erets Israel and in Egypt, it was once permissible also during the day). A custom that developed in synagogues was to have a calendar on the wall indicating which day had been reached in the counting of the Omer (sefirat ha-Omer). This practice gave rise to a new form of Jewish ritual art (the "Omer counter").
While the origin of counting the Omer is traced to the biblical regulation, various rabbinic interpretations stress its relevance for Jews in the post-Temple era. Maimonides explained that the daily counting of the interval between Passover and Shavu'ot expresses the eagerness of the people to celebrate the latter festival, marking the anniversary of the Revelation and the giving of the Torah. Other teachers, in similar vein, have stressed that the freedom festival of Passover is incomplete without the Torah festival of Shavu'ot, since freedom without law can be destructive. A bridge is therefore needed to connect both festivals, with their common ideal of freedom with law. The counting of the Omer is such a bridge.
In the course of time, the weeks of the Omer period came to be overshadowed by sadness and semi-mourning: no new clothes were worn, for example, and haircuts were prohibited. The reasons for this are obscure and they are debated by Jewish scholars. The Talmud gives a possible clue when it refers to the death of 24,000 students of Rabbi Akiva following a plague which broke out during the weeks between Passover and Shavu'ot. This is said to have occurred during the Bar Kokhba revolt against Rome (132-135 CE). The manitude of the tragedy must have impressed itself on the memory of the Jewish people; though others have suggested that the story of the plague was concocted to provide a pretext for the commemoration of various tragic events during the Bar Kokhba uprising which could not be held openly under the Romans.
In rabbinic law, the Omer period is marked by various restrictions: pious Jews avoid shaving as well as forgoing haircuts, marriages are not solemnized, and public festivities are not held. Exceptions to this rule are the remaining days of the month of Nisan after Passover (although custom varies), the New Moon and Lag Ba-Omer (the 33rd day of the Omer), and latterly---among religious Zionists---Israel's Independence Day (5 Iyyar) and Jerusalem Day (28 Iyyar).
