We find in the Third Book of the Torah, "VaYikra," or Leviticus (so-called because much (but far from all) of its content is directed, for practical purposes, at the Tribe of Levi) Chapter 23, verses 15-16, the following:
"U'Sefartem lachem Mi'Mochorat HaShabbat,…"
"And you shall count for yourselves - from the day after the holiday, from the day on which the waved Omer Offering is brought, seven complete weeks. Until (but not including) the day after the Seventh Week, you shall count (until) the fiftieth day, and you shall bring a new Meal Offering to Hashem."
Jewish Tradition interprets the words "Mi'Mochorat HaShabbat," as meaning "from the day after the holiday," rather than the day after Shabbat, or Sunday. "Holiday" here means the first day of Passover. Thus, the day of the week on which Shavuot, the fiftieth day after the beginning of the count, falls, varies and is not always Sunday.
There was a group, called the Tzedukim, who rejected the Traditions of the Rabbis. They interpreted the Torah strictly literally, and insisted that HaShabbat, as in the above verse, meant only the Seventh Day; for them, Shavuot therefore always fell on Sunday. They accepted only the Written Law, but rejected the Oral Law.
For example, when the Torah says, "Lo teva'aru esh b'chol moshvoteichem b'Yom HaShabbat," "Do not light any fire in all your dwellings on the Day of Shabbat," they understood that to mean that Jews were to stay in cold, dark houses, and eat only cold food on Shabbat. The Oral Law would explain that a pre-existing flame, lit before Shabbat, was OK; it was not the Torah's intention that we should not have any flame, just that we should not light a flame! (How could we possibly have survived without hot chicken soup and chulent?)
The beauty of "Halachah," the Jewish way of life, which recognizes both the Written and the Oral Law as being of Divine Origin, is that it is able to harmonize statements which may appear unreasonable by themselves with the clarifying light and interpretation of the Oral Law, which also came from Sinai. (What, after all, was Moshe doing for forty days and forty nights on Mount Sinai, if not learning and internalizing the Oral Law from the Master Teacher!)
When does the Count begin?
The Count begins on the night of the sixteenth day of Nisan, preceding the day on which the Omer Offering was brought at the Temple. In modern times, in Israel, this is the First Intermediate Night of Passover. In the "Golah," the Exile or Diaspora, it is the night of the Second Seder.
When does the Count end?
The Count ends on the forty-ninth night, the night before the Festival of Shavuot. Shavuot would be the fiftieth night. But it's not part of the Count. Instead, it is like the "Yovel," the Jubilee Year, the fiftieth year which follows seven Shemittah cycles, the Year of Freedom. Shavuot, which commemorates the Giving of the Torah by G-d to Man, represents Spiritual Freedom, in that it raises man above idol worship, self-worship and superstition. Our act of accepting the Torah also represented our decision to dedicate our lives to the service of the one legitimate "master," Hashem, the Creator.
Should a person be in any particular position when counting (sitting, standing, leaning (on one's left side) lying down)?
Every person who is able to, should stand while counting.
How Does One Count?
1, 2, 3,… or
2, 4, 6, …
Stop! The Question was, "With what formula does one count Sefira?"
OK! The chemical formula for table salt, an important ingredient in Jewish cooking, is NaCl, or Sodium Chloride.
Seriously, the formula for counting each of the forty-nine nights of Sefirat HaOmer is given by the Transliterated (Alef Bet to English Alphabet) and Translated Sefirat HaOmer Counting Chart, (what a mouthful!) derived from The Seif Edition of the Transliterated Siddur (Weekday Version).
Is there a Sefirat HaOmer Calendar for this Year?
For a Calendar-like Chart linking English Dates to Sefirat HaOmer Counts for this year, see the Sefirat HaOmer Calendar.
Is there a "bracha," or blessing, made in connection with the Counting of the Omer?
Vas far a qvestion! There's a blessing for everything in Judaism. In fact something is said - a bracha, before the counting and something said - a (short) prayer, after the counting, as follows:
Before, The blessing:
"Baruch Ata Adon-y, Eloh-ynu Melech Ha-Olam,"
"Blessed are You, Hashem, our G-d, King of the Universe,"
"asher kiddeshanu b'mitzvotav,"
"Who sanctified us with His commandments,"
"v'tzivanu al Sefirat HaOmer."
"And Commanded us regarding the Counting of the Omer."
Afterwards, the prayer:
"HaRachaman hu Yachazir Lanu"
"O Compassionate One! May He return for us"
"Avodat Bayt HaMikdash Li'mekomo"
"the Service of the Temple to its Place"
"bimhayra be'yameinu. Amen; Selah."
"speedily and in our time. Amen; Selah.
In the above prayer, we give expression to our desire for the Return of the Temple Service, which will be a hallmark of the Time of the Mashiach.
Various customs exist which include additional prayers before and after the counting.
What if one forgets to count?
If one forgets to count at night, he or she repeats the count the following day without a "bracha," and then resumes counting with a blessing that night. If one forgets to count in the daytime as well, it's "wait till next year" time as far as counting with a "bracha" is concerned. But one should continue to count on subsequent nights without a "bracha."
If one is unsure whether one counted, the nightly count should be continued, with a bracha.
How does one ask for a reminder of the Count?
Better, how does one reply to such a question? The problem is that if the response is, say, "No problem! Tonight we count forty-eight," the person who responded in that fashion has already counted(!) and may not count again (this night or day) with a "bracha."
The proper response to the above question would be "Last night we counted 'forty-seven.' By doing so, one has not counted "by accident" tonight.
What if the "bracha" were recited by an individual without knowledge of the Count, but with the intention of counting in accordance with what one hears from the rest of the congregation?
It is best to count with knowledge of the correct Count in mind, but if the counting is performed in the manner described above, the obligation has been fulfilled.
If the "bracha" was recited with the wrong number in mind, but the counter heard the correct information from the congregation, and counted correctly, has the obligation of Counting been fulfilled?
An Interesting Contrast:
On Purim, everyone else present in the synagogue listens to the blessing of the "Koreh," the Reader, answers "Amen" to it, and listens to every word of the Megillah. The "Koreh" has in mind to enable the listeners to fulfill their obligations. And it works!
During the period of Sefirat HaOmer, the Counting of the Omer, on the other hand, consider person A , let's call him "Reuven," for argument's sake, listening intently to person B , let's call him "Shimon," for argument's sake, pronounce the blessing and count. Reuven answers "Amen" to Shimon's blessing and concentrates on the count; although Shimon has in mind to enable the listener, Reuven, to fulfill his obligation, it doesn't work! And if Reuven does not count again by himself that night or the next day, he may not resume the count with a blessing.