On the day of the first fruits, when you offer up a new grain-offering to G-d, your [festival] of weeks, you must celebrate a holy occasion; you must not perform any mundane work.
Numbers 28:26
Allegorically, the term “first fruits” refers to the souls of the Jewish people, who are called “the first of His produce” because they were the first entity to arise in G-d’s thought before He created the world – meaning that He created the rest of the world (including the Torah itself) in their merit.
This is why Shavu’ot, the holiday on which we re-experience the Giving of the Torah, is called “the day of the first fruits.” The renewal of the Giving of the Torah is accomplished by the Jewish people, on behalf of all humanity. The Torah on its own cannot accomplish G-d’s purposes in the world; only we, using the Torah as our guide, are able to bring the world to its true completion and perfection.
—From Daily WIsdom