The names of the festivals reflect the agricultural seasons in which they take place. Thus we read: “Three times a year, you shall hold a festival for Me: You shall observe the Festival of Unleavened Bread (Pesaḥ) – eating unleavened bread for seven days as I have commanded you – at the set time in the month of Aviv, for in it you went forth from Egypt; and none shall appear before Me empty-handed; the Festival of the Harvest (Shavu’ot), of the first fruits of your work, of what you sow in the field; and the Festival of Ingathering (Sukkot) at the end of the year, when you gather in the results of your work from the field” (Shemot 23:14-17). Pesaḥ is celebrated in the spring, when everything begins growing. Shavu’ot is celebrated at the completion of the harvest and the beginning of the fruit-picking. Sukkot is celebrated when all the year’s fruit has been gathered. The natural processes that take place in this world reflect the spiritual processes that take place in the supernal world. The festivals disclose the spiritual content of this world and elevate nature’s yearly cycle. Pesaḥ takes place during a season of new beginnings and renewal. Therefore, it is at this time that we left Egypt and became a nation. Shavu’ot takes place during a season when a process of growth has peaked. Therefore, it is at this time that we received the Torah. Sukkot takes place during a season of summation, when we manifest the privilege of living our lives in the shelter of God’s providence (above 1:2).
The holiday of Shavu’ot is also the day on which the fruits of the tree are judged (RH 16a), because the first of the fruits start to ripen at about this time. Various fruits continue to ripen over the course of the summer, up until around Sukkot. On Shavu’ot, God passes judgment on the crop of fruit and determines its quantity and quality.
Thus we see that Shavu’ot is a type of Rosh Ha-shana for plant life, both fruits and grains. As we just explained, Shavu’ot is the judgment day for fruits. Grains, the staple food of humanity, finish growing then: barley begins ripening around Pesaḥ time, and other grains continue to ripen until Shavu’ot, when the wheat crop matures. Accordingly, Shavu’ot is called the Harvest Festival.
Ezra ordained that we read the curses at the end of Vayikra just before Shavu’ot and the curses at the end of Devarim just before Rosh Ha-shana as an expression of hope that the current year’s curses have come to an end, leading people to repent in hopes of assuring a blessed new year (Megilla 31b). Nowadays, though, in practice, the curses are usually read two weeks before Shavu’ot and two weeks before Rosh Ha-shana, because we do not want to place these curses in such close proximity to the festivals (Tosafot ad loc.; R. Goren, Torat Ha-mo’adim, p. 437).
On the Harvest Festival, farmers harvest the fruits of their labor; they finish harvesting the grain and begin picking the fruit. Similarly, from a spiritual perspective, on Shavu’ot the Jewish people harvested the fruits of their ancestors’ labor and were privileged to receive the Torah. Two processes were brought to completion on Shavu’ot with the giving of the Torah: first, the lengthy process that began when our ancestors started to follow God’s ways, and which continued with the self-sacrifice of the generations enslaved in Egypt; second, the shorter process of spiritual growth during Sefirat Ha-omer.