The Torah was given by God to the Jewish people on Mount Sinai more than 3300 years ago. Every year on the holiday of Shavuot jews renew their acceptance of God’s gift, and God “re-gives” the Torah.
The word Shavuot means “weeks.” It marks the completion of the seven-week counting period between Passover and Shavuot.
The giving of the Torah was a far-reaching spiritual event—one that touched the essence of the Jewish soul for all times. Sages have compared it to a wedding between God and the Jewish people. Shavuot also means “oaths,” for on this day God swore eternal devotion to the Jewish people, and they in turn pledged everlasting loyalty to Him.
In ancient times, two wheat loaves would be offered in Holy Temple. It was also at this time that people would begin to bring bikkurim, their first and choicest fruits, to thank God for Israel’s bounty.
The holiday of Shavuot is a two-day holiday, beginning at sundown of the 5th of Sivan and lasting until nightfall of the 7th of Sivan. (In Israel it is a one-day holiday, ending at nightfall of the 6th of Sivan.)
Source: chabad.org
In 2017 Shavuot in USA falls on May 31.