Counting of the Omer (Hebrew: סְפִירַת הָעוֹמֶר‎, Sefirat HaOmer, sometimes abbreviated as Sefira or the Omer) is an important verbal counting of each of the forty-nine days starting with the Wave Offering of a sheaf of ripe grain with a sacrifice immediately following the commencement (Hebrew: רֵאשִׁית‎, reishit) of the grain harvest, and the First Fruits festival celebrating the end of the grain harvest, known as Feast of Weeks/Shavuot/Pentecost in Mosaic Law (Hebrew Bible: Deuteronomy 16:9–12, Leviticus 23:10–16); or in the varying current Jewish holidays traditions, the period between the Passover or Feast of Unleavened Bread, and Shavuot. This is the second of the three annual Mosaic Law feast periods.