'OMER (= "sheaf").
The Israelites were commanded after the conquest of Canaan to bring at harvest-time an 'omer of the first-fruits to the priest as a wave-offering (Lev. xxiii. 10-11). The day on which the 'omer of the wave-offering had to be brought is vaguely indicated as "on the morrow after the Sabbath." It would appear from Lev. xxiii. 11 that the priest had only to wave it on the morrow of the Sabbath, while it might be brought on some previous day; but verse 15 of the same chapter shows that the bringing and waving were to take place on the same day. That day required a special sacrifice after the waving of the 'omer, namely, a "he-lamb without blemish of the first year for a burnt offering, two tenth parts of an ephah of fine flour with oil for a meal-offering, and of wine the fourth part of an hin for a drink-offering." The Israelites were forbidden to eat of the newly harvested grain till after they had brought the sacrifices of the 'omer (ib. verses 12-14). From the day on which the 'omer of the wave-offering was brought the Israelites had to count seven weeks or forty-nine days, the fiftieth day being the Feast of Pentecost (ib. verses 15 et seq.). The counting is still practised; and, though the bringing of the 'omer ceased with the destruction of the Temple, the days between Passover and Pentecost are called the "'omer days" (see Pentecost).—In Post-Biblical Literature:
The Rabbis, contrary to the Septuagint and later non-Jewish translators, consider the word "'omer" as designating the measure, which is one-tenth of an ephah (comp. Ex. xvi. 36; A. V. "omer"); therefore they hold that the wave-offering did not consist of a sheaf but was an 'omer of grain (see Rashi to Lev. xxiii. 10). They assert also that although the kind of grain is not specified in the Bible the only sort which could be used for the offering was barley (Pesiḳ. viii. 70a; Men. 68b). The grain had to be reaped on the day, or during the night preceding the day, it was to be brought into the Temple (Meg. 20b; see below). According to the Rabbis, the wave-offering was brought on the 16th of Nisan, that is, on the morrow after the Passover Feast, the main point of difference between the Rabbis and the Boethusians and modern Karaites being that the latter explained literally the words "morrow after the Sabbath" (Lev. xxiii. 15) as the day following the first Sabbath after the Passover Feast (Men. 65b; Meg.Ta'an. i.).Regulations Concerning the Reaping.
Although the ephah contained three seahs (see Targ. pseudo-Jonathan to Ex. xvi. 36; see also Weights and Measures), so that the 'omer became one-tenth of three seahs, yet, according to R. Ishmael, if the 16th of Nisan is a week-day, five seahs of barley must be reaped, for after the grain has been cleaned and sifted several times only three seahs will remain. If the 16th of Nisan falls on a Sabbath, only three seahs must be reaped, for otherwise the work would take too long. According to the other rabbis, the quantity to be reaped was always three seahs. There arose a difference also between R. Ḥanina Segan ha-Kohanim and those who asserted that the grain for the 'omer must always, even on a Sabbath, be reaped by three persons, each with his own sickle and basket, in order to give the reaping more publicity; R. Ḥanina Segan ha-Kohanim declared that on a Sabbath only one man might reap the 'omer, with one sickle and one basket (Men. vi. 1). Thegrain must be taken from a field near Jerusalem, if ripe enough; otherwise it may be gathered elsewhere (Men. vi. 2).
The reaping was done with much ceremony. Messengers, sent by the bet din to the chosen field on the day preceding the Passover Feast, drew the heads of the stalks together in sheaves and tied them in order to facilitate the work of the reapers. Then when the hour for gathering came the reapers thrice asked permission to reap; this was done in order to impress upon the Boethusians that this was the proper time for the gathering of the 'omer (Men. vi. 3).Manner of Waving the 'Omer.
After the grain had been gathered it was brought to the courtyard of the Temple, where, according to R. Meïr, it was parched while it was still in the ear; according to the other rabbis, it was first thrashed and then parched. The grain was ground into coarse meal and then sifted through thirteen sieves until it became very clean, after which the tenth part was taken, the measure of the 'omer, and given to the priest. The remainder, which was subject to ḥallah, and, according to R. Akiba, to tithe also, could be redeemed and eaten even by laymen. The priest proceeded with the 'omer as with any other meal-offering: he poured oil and frankincense over the meal, "waved" it, and then burned a handful of it on the altar; the remainder was eaten by the priests (Men. vi. 4). The "waving" was done in the following way: The offering was placed on the extended hands of the priest, who moved them backward and forward (to counter-act the effects of injurious winds) and then upward and downward (to counteract the effects of injurious dews; Pesiḳ. R. xviii. [ed. Friedmann, p. 92a]; Pesiḳ. viii. 70b; Men. 62a; Lev. R. xxviii. 5). As soon as the 'omer ceremony was completed the people of Jerusalem were permitted to eat of the newly harvested grain; people of towns far from Jerusalem might not do so until after noon, when it was certain that the ceremony at Jerusalem had been concluded. After the destruction of the Temple, R. Johanan b. Zakkai decided that the new grain might not be eaten at all during the 16th of Nisan (Men. vi. 5). No grain might be reaped until the barley for the 'omer had been gathered (Men. vi. 7).
The Rabbis considered the bringing of the 'omer as one of the most important observances: it is a repayment to God for the manna given in the wilderness, of which every Israelite collected the measure of an 'omer (see Manna). God made the repayment so easy that only the quantity of one 'omer, and that of barley only, was required from all Israel. The virtue of the 'omer was so great that, according to the Rabbis, on its account God promised the land of Canaan to Abraham. The 'omer made peace between husband and wife, that is, the meal-offering of jealousy did, which consisted of the tenth part of an ephah of barley-meal (comp. Num. v. 15). It was the 'omer that rescued the Israelites from the Midianites in the time of Gideon, from the Assyrians in the time of Hezekiah, from the Babylonians in the time of Ezekiel, and from the Amalckites in the time of Haman (see Mordecai in Rabbinical Literature), these conclusions being inferred by the Rabbis from the word "barley" mentioned in connection with each of these events (Pesiḳ. R. l.c.; Pesiḳ. l.c.; Lev. R. xxviii. 4-6).