Shavuot, the Festival of Weeks, is also referred to in the Bible as Hag HaBikkurim, Festival of the First Fruits.
In Judaism, agriculture is imbued with spirituality through all the practices associated with it. The Bible legislates when to toil the land, when to refrain from working it, and how to use its produce in an ethical manner.
One of the religious experiences connected to farming was the offering of produce in the Holy Temple. In Temple times,
Jews from all over the land of Israel trekked to Jerusalem on Shavuot to offer their first fruits of the new season, giving rise to the name Chag Habikkurim, Festival of the First Fruits. This pilgrimage was one of three that were required of all Jews who were able.
Shavuot, with its wheat offering in the Temple, also marked the end of a harvest cycle, which began when the barley crop was offered on Pesach.
Barley was used as animal feed, whereas wheat was generally saved for human consumption. Indeed, the two offerings represent the movement from the animalistic, slave existence of Egypt (the Pesach offering) to the elevated experience of human beings created in the Divine image who enter into a relationship with God (the revelation at Sinai on Shavuot). Thus the wheat offering of Shavuot was a culmination of the 0mer period in metaphysical as well as agricultural terms.
Today we recall the harvest aspects of the festival through customs such as decorating with flowers, fruits and greenery, and reading the Book of Ruth.