An omer is a tenth of an ephah. These are dry measures that were used in ancient times. An “omer” may also mean a “sheaf” of grain, in this case barley, and that is what we are counting during these days.
In Leviticus 23:9-11 (this week’s parashah!), we read that we were forbidden to use any of the newly grown grain until an omer of it was taken to the Temple as an offering. The priest would “elevate” it before God on the day after Sabbath on your behalf. Then in Leviticus 23:15-16, we see that we are further commanded to count off seven whole weeks – since they must be complete weeks we make it 50 days, and then we bring an offering of new grain to the Temple. This is quite an elaborate offering that we must take before God at that point, and we are advised that everyone should celebrate.
Eventually, those in charge calendared this to begin on the second day of Passover by making an offering of an omer of grain, and then keep counting each day.
Called Sefirat HaOmer, Counting the Omer, the ritual bridges the days between Passover and Shavu’ot, thus linking the Exodus from Egypt with receiving the Law at Mount Sinai. In other words, this period of time joins our physical redemption with our spiritual redemption.
Of course, we no longer take grain (an omer would be about a handful as a dry measure or an armful as a sheaf) to the Temple. But still we say a special berakhah every evening at sundown to count the next number, and say a special prayer, and some read a psalm (after the first verse, there are exactly 49 words in it).
Many rituals and superstitions (my dad would have called them einredenishes) have arisen about counting the omer. Rabbi Akiba lost 24,000 students to a plague during the omer period. Superstitions come and go.
Some have said that during this period we are partially in mourning – don’t have weddings, parties, or dinner dances, don’t get haircuts. On the 33rd day – Lag BaOmer (if you write numbers with Hebrew letters, it spells “lag”) – we get a break because Rabbi Akiba’s students got a break in the plague. On Lag BaOmer we can dance and get married and whatnot, and many say thereafter we can party on, plague over.
There is even an app to help – Omer: A Counting. I have not tried it. I use the back of this Bulletin. Counting our good fortune – our harvest – together as a community is the richest part of this blessing.