Shavuot, also called Pentecost, The Feast of Weeks, or First Fruits, represents a foundational moment in Jewish history: the giving of the Torah (the first five books of the Bible, also called the Pentateuch) to the Israelites on Mount Sinai.
The date of celebration falls seven weeks after Passover; on the Gregorian calendar, it starts on June 7th at sunset and ends at nightfall (about an hour after sunset) on June 9th. Passover was the day the Hebrews escaped from Egyptian slavery; Shavuot is considered the day that God made them into their own nation.
The story of the giving of the Torah begins in Exodus 19 and continues from there:
On the first day of the third month after the Israelites left Egypt—on that very day—they came to the Desert of Sinai. After they set out from Rephidim, they entered the Desert of Sinai, and Israel camped there in the desert in front of the mountain.
Then Moses went up to God, and the LORD called to him from the mountain and said, “This is what you are to say to the descendants of Jacob and what you are to tell the people of Israel: ‘You yourselves have seen what I did to Egypt, and how I carried you on eagles’ wings and brought you to myself. Now if you obey me fully and keep my covenant, then out of all nations you will be my treasured possession. Although the whole earth is mine, you will be for me a kingdom of priests and a holy nation.’ These are the words you are to speak to the Israelites.”
So Moses went back and summoned the elders of the people and set before them all the words the LORD had commanded him to speak. The people all responded together, “We will do everything the LORD has said.” So Moses brought their answer back to the LORD.
The LORD said to Moses, “I am going to come to you in a dense cloud, so that the people will hear me speaking with you and will always put their trust in you.” Then Moses told the LORD what the people had said.
Traditions around Shavuot include: