The Hebrew word Shavuot can also be interpreted as “oaths”. This day is believed to be the same day on which the Torah was given at Sinai, G-d making an oath to us and we to Him. Shavuot was celebrated as a time of gladness concluding the grain harvest, much like Sukkot concludes the fruit harvest. It was the first day on which first fruits offerings were brought to the Temple. Thus in the Bible it is also known as the Festival of Reaping and the Day of First Fruits.
The festival of Shavuot arrived, and the believers all gathered together in one place. Suddenly there came a sound from the sky like the roar of a violent wind, and it filled the whole house where they were sitting. Then they saw what looked like tongues of fire, which separated and came to rest on each one of them. They were all filled with the Ruach HaKodesh and began to talk in different languages, as the Spirit enabled them to speak.
Acts 2:1-4 (CJB)
As the apostles gathered to celebrate this feast, another oath was fulfilled to them – the promise of the Holy Spirit.
You shall count fifty days to the day after the seventh Sabbath. Then you shall present a grain offering of new grain to the L-rd.
Leviticus 23:16 (ESV)
This is the only holiday for which the Torah does not indicate a specific date, rather it is counted from the Sabbath during a previous holiday. For this reason, there is different interpretations among Jewish sources about how to count, and which day the holiday falls on. Orthodox Judaism holds that seven weeks are to be counted starting the day after the high sabbath of Passover, the first day of Unleavened bread. Thus, in the above verse “Sabbath” would be interpreted “seven-day period” and Shavuot would always fall on the sixth day of the Hebrew month Sivan. However, others such as the Karaites, the historical Sadducees, and also Catholics hold that counting should begin the day after the regular Sabbath, therefore Shavuot would always fall on Sunday fifty days later. We at Beth El Shaddai respect both interpretations, but hold our celebration according to the later.