וּסְפַרְתֶּם לָכֶם,מִמָּחֳרַת הַשַּׁבָּת,מִיּוֹם הֲבִיאֲכֶם,אֶת-עֹמֶר הַתְּנוּפָה:שֶׁבַע שַׁבָּתוֹת,תְּמִימֹת תִּהְיֶינָה– And from the day on which you bring the sheaf of elevation offering – the day after the Sabbath [yom tov of Passover] – you shall count off seven weeks, they must be complete. (Leviticus 23:15)
This verse found in parshat Emor is the instruction from which we learn we are to daily ‘Count the Omer’ (Sefirat HaOmer) – the 7 weeks between Pesach and Shavuot. Question: why are there not two counts made each night in the Diaspora similar to the practice of Yom Tov Sheni? The answer is contained in the commentary of the Magen Avraham (17th century, Poland) on the Shulchan Arukh who teaches that if a person does not understand Hebrew and counts the Omer in Hebrew that person has not fulfilled the mitzvah of the counting. He was challenged by others who said that since there is no requirement to understand the Hebrew of Kiddush or Hallel and the like, why should it be so for the ‘counting’? Says the Magen Avraham that for those other ritual elements it is the reading or saying of them that is required, but the essence of counting is the knowledge and certainty of the day being counted. Despite the diasporic practice of celebrating extra days of the pilgrimage festivals, since the set calendar allows us to know the precise beginning of Pesach, we know the precise beginning of the Counting and to make two counts would be to negate the mitzvah of Sefirah.