Shavu’ot is also referred to as Yom Ha-bikurim, as we read: “On the day of the first fruits (yom ha-bikurim), your Festival of Weeks, when you bring an offering of new grain to the Lord, you shall observe a sacred occasion: you shall not do any melakha of labor” (Bamidbar 28:26).
There are two meanings of bikurim on Shavu’ot. First, Shavu’ot was the time for the offering of shtei ha-leḥem (two loaves), which was referred to as bikurim (first fruits), because it was the first minḥa offering from the year’s new wheat. Following this offering, the Jews were permitted to bring further offerings from the new grain. Earlier, on Pesaḥ, the omer offering permitted Jews to eat from the year’s new grain, but not to bring sacrifices from it (m. Menaḥot 10:6). There is a unique law which pertains to the shtei ha-leḥem offering. Even though leaven was forbidden in the Temple all year long, these two loaves were leavened. Though they were not actually placed on the altar, they were eaten by the Kohanim (see section 7 below).
The second meaning of Yom Ha-bikurim is that with the shtei ha-leḥem offering, the time had arrived for the mitzva of bikurim. In Temple times, this mitzva was relevant to anyone with a field where any of the seven species grew. The farmer was required to take the first fruits to the Temple and present them to the Kohanim. When he saw the first of his grain or fruit begin to ripen in his field, he tied a ribbon around them and declared: “These are first fruits.” When they finished ripening, he prepared them to be brought to the Temple. All of the people from the periphery who were ascending to Jerusalem for the festival gathered together and slept in the streets of their town. When dawn broke, the appointed leader announced: “Let’s get up and go up to Zion, to the house of the Lord our God.” They traveled in a procession of decorated carriages, accompanied by music. When they got close to Jerusalem, they sent messengers ahead to inform the residents that they were about to enter the city. Important Kohanim and other dignitaries went out to greet them. When they passed through the streets of Jerusalem, workmen stopped working and greeted them: “Our brothers from such-and-such: welcome.” They then ascended to the Temple Mount, singing and dancing, with the baskets of bikurim on their shoulders. Each pilgrim presented his basket to a Kohen and proclaimed: “I acknowledge this day before the Lord your God that I have entered the land that the Lord swore to our fathers to assign us” (Devarim 26:3). The Kohen then took the basket and placed it before the altar. The pilgrim continued reciting the formula as written in the Torah, including the litany of travails that the Jews experienced from the beginning of their history until their redemption, and concluded: “The Lord freed us from Egypt by a mighty hand, by an outstretched arm and awesome power, and by signs and portents. He brought us to this place and gave us this land, a land flowing with milk and honey. Therefore I now bring the first fruits of the soil which You, O Lord, have given me” (ibid. vv. 8-10). Together with offering bikurim, pilgrims generally also offered a celebratory shelamim (m. Bikurim 3:1-6).
The time to bring bikurim began with the shtei ha-leḥem on Shavu’ot and ended on Ḥanuka (m. Bikurim 1:3, 6). But the first fruits of the wheat and barley crops were brought on Shavu’ot, leading to its name of Yom Ha-bikurim.