Shavuot is an "appointed time" of Yahweh and this festival (chag) is celebrated in the Spring. In English we call this feast Pentecost, which means fifty. In Hebrew it is called Shavuot which means, "weeks". It is celebrated 50 days after the Feast of Firstfruits. Firstfruits is celebrated on the day after the weekly Sabbath following Passover. On Firstfruits (which is always on a Sunday on our Gregorian calendar) a count begins toward Shavuot. 7 weekly Sabbaths are counted (49 days), then on the day after the 7th Sabbath, we reach Shavuot (50th day). Shavuot is also on a Sunday. Shavuot was historically the celebration of the wheat harvest. On Shavuot the firstfruits of the wheat harvest were offered to Yahweh, then the harvest could begin. The weeks leading up to Shavuot are called "the Counting of the Omer". Shavuot is also known by the names: Feast of Weeks, Festival of Firstfruits, Harvest Festival, and Season of our Liberation.
On Shavuot two loaves of wheat bread were offered before Yahweh, these loaves contained yeast or leaven. This is the only mention of God accepting leaven to be offered to Him because leaven represents sin. Most Messianic Hebrew scholars explain this to mean Jew and Gentile coming together as one new man to Messiah, the cultivated and the wild olive trees. Hebraically the thought is also that the two loaves represent the two tablets of the covenant which were written with the finger of YHVH.
Historically, Shavuot represents the giving of the Torah on Mt. Sinai when the people came into covenant with Yahweh. It is recorded in Jewish tradition that 7 weeks after leaving Egypt, the Torah was given to the Children of Israel at Mt. Sinai. The giving of the Torah is still celebrated today on Shavuot.
The event in Jerusalem, in Acts chapter 2, on the day of Shavuot, (Pentecost) marks the giving of the renewed covenant in Messiah where He wrote His laws upon our heart and it completely parallels the event at Mt. Sinai; fire, smoke, wind. Read the passages in Exodus 19:16-17 and Acts 2:1-3. See the parallel events? Wind, fire, clouds, sound from heaven. Both of these events happened on the same day, Shavuot. God follows patterns. Also, 3000 were killed at Mt Sinai for disobedience, while 3000 were saved and added to the assembly at the same event in Acts when Peter finished preaching.
Jewish tradition also states that at Mt. Sinai God spoke in every language (simultaneously) as He uttered His Ten Words (Commandments). It is stated that as His Words were spoken that they proceeded forth as fire which lit upon the heads of each individual standing there. This also correlates with the "tongues of fire" spoken of in Acts Chapter 2.
About 1500 years before Sinai, the Jews say that another event happened on what would have been the date of another Shavuot, that was the destruction of the tower of Babel. At Babel, God confused the language of the people as a result of their misusing their unity for wicked purposes. At Jerusalem, in Acts 2, God caused people whose different languages separated them to now understand each other as they praised God, which is the proper use of unity. At Shavuot in Acts chapter 2, Yahweh reversed the curse at Babel. At Babel mankind lost the ability to communicate through speaking various languages, due to their rebellion against God. In Acts chapter 2 a removal of this penalty of rebellion was the gift of tongues, described as tongues of fire, ushering in a full restoration of the earth’s unity of language or WORSHIP, which is still going to be completed in the future with the coming of Messiah Yeshua.
In Zephaniah 3:9 Yahweh speaks about restoring a pure language, (saphah berurah). A better translation of this scripture, although one language will no doubt be restored, is to mean that Yahweh will restore ONE form of religious WORSHIP TO Him only, and no other false gods will ever be worshiped again. For thousands of years man has worshiped other false gods, a language or better yet, a WORSHIP that He does not RECOGNIZE or APPROVE. Yahweh promises to restore His PURE WORSHIP.
This meaning is apparent in Psalms 81:5 where Yahweh, as the speaker, states that he heard a language which He understood not. Of course, Yahweh understands all languages, it should be rendered “where I heard a WORSHIP which I approved not”, because they were calling out to false gods.
Shavuot is also known as the “Season of Our Liberation". Shavuot was a completion of the experience of redemption brought about by the Passover out of Egypt. At Mt. Sinai Yahweh revealed Himself to them. He did not bring them out of Egyptian bondage to only bring them to Sinai and put them back under bondage with the Torah. No, He brought them to Sinai and gave them the Torah to liberate them, to bring them into freedom. The Exodus from Egypt lead them to Sinai for a revelation of their God.
In Leviticus 23: 1-44 the Feasts of Yahweh are listed and instructions given. The Feast of Shavuot is listed in verses 15-22. In Exodus 23:14-19 Shavuot is again mentioned. If you will notice, in the Hebrew text, the Feast of Shavuot is called not only a moed (appointed time), but also a (feast) chag. Chag in Hebrew means “to march in a sacred procession, to observe a festival, to be giddy, dance etc”. Three times a year, all males were to go up to Jerusalem to celebrate before their God. These were very joyous celebrations. The three commanded pilgrimages were Unleavened Bread, Shavuot, and Sukkot (Tabernacles). Understanding the Festival of Shavuot within its historical and Biblical context one would be able to understand why so many people had gathered in Jerusalem in Acts chapter 2. They had made the annual pilgrimage to Jerusalem to celebrate the Festival as commanded by Yahweh.
On one day in the future Yahweh will complete His job of writing the Torah upon our hearts through His son Yeshua.