usfartem lakhem mimahorat hashabat miyom haviakhem et omer (Levit. 23:15) ('and [each of] you shall count from the morrow of the day of rest, from the day on which you bring the "Omer"') Nowadays this Mitzva is carried out either because the commandment of the Torah is still effective (despite the fact that we do not sacrifice the "Omer" on the first day of Hol haMoed Pesah), or because it is rabbinically ordained. How is the Mitzva to be carried out?

In his encyclopedic work on halakha, Bet Yosef (O.H. 489), Rabbi Yosef Karo (16th century) quotes the Rashba (13th century) responding to a questioner to the effect that saying hayom kakh vekhakh ('Today it is such and such') is sufficient, however adding the word laOmer ('of/to the Omer') serves to clarify the statement. He also quotes Rabbenu Nissim (Ran, 14th century), who mentions laOmer. On the other hand Sefer haMinhagim, an Ashkenazi work of the same era, states that one should conclude with baOmer ('in the Omer').

In his far more popular work, Shulhan Arukh (O.H. 489:1), Rabbi Karo lays down that one is required to say hayom yom ehad ('Today it is one day.'), and at that point Rabbi Moshe Isserles (Rema, 16th century) in his commentary Mapa inserts the word baOmer in small Rashi script in brackets. (It is not clear how, in the Shulhan Arukh accompanying the Mishnah BeruraH, the print of the Rema became square and regular size. This can cause confusion.) The Rema here is not disagreeing; he is indicating what he considers the lekhat'hila ('preferable') manner of carrying out the Mitzva. Indeed he is following one of two well-established traditions.

From then till our own day there has been a continuous debate as to what is the exact meaning of each of these two versions. If the prefix Lamed means a reference to time elapsed since an event how can it be used on the first evening? If Omer is the name of the sacrifice of the first barley of the season how can one count "in" it? Among the first to deal with these issues were Rabbi David ben Shemuel haLevi, (1586-1667) in his commentary (Taz) on the Shulhan Arukhnm who prefers baOmer; and Rabbi Shabbetai Sofer (b. before 1589 d. before 1648) in his commentary to the Siddur who prefers laOmer. Rabbi Judah Ashkenazi in his commentary on the Shulhan Arukh introduces a new factor: he writes that the Ari, the most widely accepted exponent of the Kabala, prefers laOmer. It is then not surprising that Rabbi Isaiah Horowitz in his Shenei Luhot haBerit (Shela), a kabalistic work, also prefers laOmer. Despite the fact that Rabbi Elijah the Gaon of Vilna was a follower of the Ari's kabala, Maase Rav, a book dealing with the customs of the Gaon, reports that he said baOmer. The Mishnah Berurah (a commentary on Orah Haim, the first section of the Shulhan Arukh by Rabbi Israel Meir Kagan best known as the author of Hafetz Haim) states that though the majority of commentaries prefer laOmer, it is not necessary to say it that way. The siddurim of both Baer (Avodat Israel) and R. Hirsch have laOmer. The Yemenite siddur Takhlel torat avot nusah baladi, gives the counting in Aramaic and has be'omra, with a Bet.

This leads us to ask: "which is the older version?" In principal it may be said that when two customs are found, the first in two geographic areas far apart from each other, and the second between these two, the second is the later custom superseding the first. This is because it is unlikely that the same custom should occur independently in two places. According to this theory the prefix Bet for baOmer was the older version, as it was known only in northern Europe - the extreme north of the Diaspora, and in Yemen - the extreme south of the Diaspora.

It is clear that one fulfils the Mitzva fully by counting according to all the standard versions in use, and these issues should never be used to divide Jews. May we complete the count and relive the giving of the Torah together.