Celebrated on the 50^th day, or seven weeks after Passover, Shavuot is a one-day event in Israel and a two-day holiday in the Diaspora. The holiday commences at sundown following the 5th of Sivan and lasts until nightfall on the 7th of Sivan (or 6^th Day of Sivan in Israel). On the Gregorian calendar, this corresponds to variable days in the latter part of May or early June.

Shavuot has multiple names: 

• Hag Shavuot, "the festival of weeks" (Exodus 34:22, Deuteronomy 16:10, 2 Chronicles 8:13)
• Day of Firstfruits (Numbers 28:26)
• Feast of the Harvest (Exodus 23:16)
• Pentecost (Greek pentēkostē), referring to the 50^th day from the Feast of Firstfruits (Acts 2:1, 2 Maccabees 12:32)

Part of the scripture the Jewish people use as the basis of Shavuot is as follows:

You shall count seven full weeks from the day after the Sabbath, from the day that you brought the sheaf of the wave offering. You shall count fifty days to the day after the seventh Sabbath.

Then you shall present a grain offering of new grain to the Lord. You shall bring from your dwelling places two loaves of bread to be waved, made of two tenths of an ephah. They shall be of fine flour, and they shall be baked with leaven as firstfruits to the Lord.

And you shall present with the bread seven lambs a year old without blemish, one bull from the herd, and two rams. They shall be a burnt offering to the Lord, with their grain offering and their drink offerings, a food offering with a pleasing aroma to the Lord. And you shall offer one male goat for a sin offering and two male lambs a year old as a sacrifice of peace offerings.

And the priest shall wave them with the bread of the firstfruits as a wave offering before the Lord, with the two lambs.

They shall be holy to the Lord for the priest. And you shall make a proclamation on the same day. You shall hold a holy convocation. You shall not do any ordinary work. It is a statute forever in all your dwelling places throughout your generations.

When you reap the harvest of your land, do not reap to the very edges of your field or gather the gleanings of your harvest. Leave them for the poor and for the foreigners residing among you. I am the Lord, your God. (Leviticus 23:16-22)

The spirit of counting the Omer on the second night of Passover, at the second Seder, is expressed below:

bah-ROOCH ah-TAH ah-doh-NAI eh-loh-HAY-noo MEH-lech hah-oh-LAHM, ah-SHER keed-SHAH-noo beh-meets-voh-TAHV veh-tsee-VAH-noo ahl sfee-RAHT hah-OH-mer

Blessed are You, O Lord our God, King of the universe, who has set us apart by Your commandments and has commanded us concerning the counting of the sheaf.

The holiday originally had roots in agriculture, marking the end of the spring barley harvest and beginning Israel’s summer wheat harvest. Ancient traditions surrounding Shavuot include pilgrimage festivals where Israelis brought the "first fruits" (bikkurim) of their harvests, such as two wheat loaves baked from the season’s newest wheat, to the Temple in Jerusalem. The intention was to thank God for providing a bountiful grain and fruit harvest to nourish the Children of Israel. (Besides Shavuot, the other two pilgrimage feasts include the Feast of Unleavened Bread and the Feast of Tabernacles.)

Given that the Bar Kochba revolt left ancient Israel in ruins, with numerous fortresses and villages pillaged and the Jewish death toll in the hundreds of thousands, and that the Jewish people were demographically shifting from a more agricultural people to a more urban people, Shavuot slowly transitioned from a celebration of the grain harvest to a celebration of G-d bestowing the Torah upon the Jews at Mount Sinai 3,000 years ago. This interpretation of Shavuot was advanced by the teachings of the rabbis at the time, as found in the Talmud, Pesachim 68b, which reads:

Rabbi Elazar said: All agree with regard to Atzeret, the holiday of Shavuot, that we require that it be also "for you," meaning that it is a mitzva to eat, drink, and rejoice on that day. What is the reason? It is the day on which the Torah was given, and one must celebrate the fact that the Torah was given to the Jewish people.

With the modification in how Shavuot is observed, the Jewish people no longer bring the first fruits of their agricultural bounty to the Temple in Jerusalem, as there are no particular mitzvot commanding them to do so.

Some sages liken Shavuot to a wedding ceremony between God and the Jewish people. With that understanding, Shavuot is understood as an opportunity for the Jewish people to renew their vows with God, recommitting their lives to the teachings of the Ten Commandments and the Torah. Instead of the wedding comparison, however, other sages would rather liken Shavuot to the birthday of Judaism, citing various other rabbinical writings.

The Jewish people customarily celebrate Shavuot in many ways:

• Taking time off work and completing no ordinary work
• Staying up throughout the night to study the Torah
• Women and girls light candles and/or host candlelight dinners for friends and family
• Partaking in dairy foods such as cheese blintzes (cheese rolled in pancakes, shaped into triangles, and fried in a skillet, with the Sephardic equivalent being referred to as bourekas), quiches, cheesecakes, and more
• Some communities enjoy honey in addition to dairy foods
• Ashkenazi communities participating in the Yizkor memorial service recited traditionally on the second day of Shavuot
• Jewish people decorating their homes and synagogues with woven canopies of fruits and flowers in honor of the spring harvest and the ancient traditions of bringing the first fruits to the Temple, or braiding a crown of branches and flowers for the Torah scrolls.
• Attending synagogue services to hear readings on the Ten Commandments and recitations of the Hallel, the Psalms of Praise
• Participating in community events where the Scroll of Ruth is read
• In some Sephardic communities, reading a ketubah l’Shavuot, which is a symbolic marriage covenant established between G-d and the Jewish people

Many people wonder about the origins of incorporating dairy foods and, in some cases, sometimes honey into Shavuot festivities. It is believed the Jewish people have extrapolated the tradition from scripture, citing a "land flowing with milk and honey" (Exodus 3:8), "milk and honey are under your tongue" (Song of Songs 4:11), and "the precepts of the Lord are... sweeter than honey" (Psalm 19:9–11). The foods help Jewish families remember the "sweetness" of the Torah.

In addition to the foods referenced above, some Jewish people enjoy kreplach, small dumplings, typically made by wrapping a filling, such as meat, vegetables or cheese. The symbolism emphasizes the number three, as explained by ancient rabbis: "Blessed be the Merciful One who gave the threefold law [Torah (law), Nevi’im (prophets), and Ketuvim (writings)] to a people made of three classes [priests, Levites, and Israelites] through a third-born child [Moses was born after Miriam and Aaron] in the third month [Sivan]." In modern times, the number three still bears some significance as the Jewish people utilize the three days before Shavuot to practically and spiritually prepare themselves, their families, congregations, and communities for Shavuot.

Related to traditional foods but unrelated to dairy, many modern Jewish families have adopted the tradition of baking two loaves of challah bread on Shavuot to represent the two loaves of wheat bread offered in the Temple as well as the two tablets of the Torah.

Why the tradition of staying up late all night studying the Torah? Historians believe this Shavuot tradition originated from the narrative that the Israelites overslept at Sinai and had to be awakened from their slumber by Moses. Therefore, to correct their past mistake and demonstrate to G-d that the Jewish people would not fall asleep like previous generations did, the Jews of today fostered the tradition of staying up throughout the night, or at least long past sundown, to study and celebrate Torah. Of course, in modern times, these all-night parties will include periodic breaks for cheesecake and caffeine sources. The custom has taken on the name "Tikkun Leil Shavuot," which translates to "Rectification for Shavuot Night." The whole point of the tradition is for the Jews to develop a closer relationship with G-d through the study of the law.

Tikkun Leil Shavout was not found in some early Zionist communities who wanted to put less emphasis on religion. More recently, however, this practice has exploded in popularity among the Jewish people, both in Israel and the Diaspora. The Jews of many communities will travel from gathering to gathering throughout the night (tikkun to tikkun—between various homes, synagogues, community centers, parks, schools, etc. where Shavuot gatherings are being hosted) for Torah study and fellowship.

Interestingly, confirmation ceremonies, essentially graduation ceremonies for Jewish students who have graduated from Jewish Sabbath schools, are traditionally held on or around Shavuot (e.g., the weekend nearest Shavuot). These confirmation ceremonies tie in with the Shavuot theme as these young scholars and future community leaders, typically ages 12–13 and dressed in their best clothes for a ceremony at the local synagogue, reaffirm their commitments to G-d and to Jewish life going forward as adults. For some young adults, this confirmation ceremony would replace the Bar/Bat Mitzvah. In other cases, it would function as a supplemental event to the Bar/Bat Mitzvah to celebrate the end of the school year. Regardless, the event is usually connected to the Shavuot celebration in its timing.

What does the Book of Ruth have to do with Shavuot? While the story is read during Shavuot services, the purpose has to do with Ruth’s choice to convert to Judaism and accept the Torah as foundational to her relationship with G-d, grafting Ruth into the Land of Israel, as the Jews collectively accepted the Torah as foundational to their relationship with G-d at Mount Sinai. Furthermore, the story of Ruth occurred during the spring barley harvest.

The story of Ruth, however, as many are aware, goes deeper than the story of Ruth and Boaz and Ruth’s acceptance of the Torah. It is a profound foreshadowing of the redemptive love of God. Ruth goes on to become the great-grandmother of David, the first King of Judah, which would ultimately lead to our Messiah and our Messiah’s redemption of all of mankind.

Ruth 4:22 says that Ruth and Boaz’s son, Obed, fathered Jesse, and Jesse’s son was David (who would go on to reign as the first King of Judah). The fact that Yeshua is a descendent of David (Matthew 1:1) suggests that our Messiah Himself is a direct descendent from Ruth and Boaz. Additionally, the genealogy presented in Matthew 1 includes Ruth and Boaz by name.

Furthermore, just as Boaz functioned as Ruth’s "kinsman-redeemer," the Book of Ruth foreshadows the coming of our ultimate Kinsman-Redeemer, Yeshua HaMashiach, who paid the ultimate price for all of our sins and whose birth in a dirty stable, life and ministry on earth, brutal death, and resurrection would be instrumental in extending salvation to all, both Jews and Gentiles.

For He Himself is our peace, who has made both one and has broken down the middle wall of separation, having abolished in His flesh the enmity, that is, the law of commandments contained in ordinances, so as to create in Himself one new man from the two, thus making peace, and that He might reconcile them both to God in one body through the cross, thereby putting to death the enmity. (Ephesians 2:14-16)

Mashiach [Messiah] was sacrificed once to take away the sins of many, and He will appear a second time, not to bear sin but to bring salvation to those who are waiting for Him. (Hebrews 9:28)

For those of us who are Christians, Shavuot is not an irrelevant Jewish holiday. Even within Christianity, Pentecost is recognized as the day the Ruach HaKodesh (Holy Spirit) descended upon Yeshua’s talmidim (disciples).

Without Pentecost and the outpouring of the Holy Spirit, we would not have the power to witness the salvation of Yeshua to the Jews or ultimately all people. As we all know, witnessing to the lost cannot be achieved by our own might or power, but only through the might and power of the Holy Spirit working on each of our hearts and on the hearts of those we hope will accept the Good News.

Do not leave Jerusalem, but wait for the gift my Father promised, which you have heard me speak about. John was baptized with water, but in a few days, you will be baptized with the Holy Spirit…But you will receive power when the Holy Spirit comes on you, and you will be my witnesses in Jerusalem, in all Judea and Samaria, and to the ends of the earth. (Acts 1:4,8)