Rabbi Schneider - Understanding Feast Weeks
The last of the spring holy days is called "Shavuot", also referred to as "Pentecost" or the "Feast of Weeks". It follows the first three spring holy days: Passover, unleavened bread, and first fruits. And this culminating spring holy day, we actually see being celebrated in the Book of Acts chapter 2. In acts 2 we read about how Yeshua's disciples had come together for the day of Pentecost had come. But many that read the New Testament don't understand, that these first believers in acts chapter 2 were not celebrating this day in the upper room originally unto Yeshua, but rather they had already been celebrating this day called "Pentecost" or the "Feast of Weeks" for 1500 years before Jesus's arrival.
We read about it in the Torah Leviticus chapter 23. It took place 50 days after Passover, or seven weeks and a day. Thus we get the term "Pentecost" meaning 50, or the "Feast of Weeks", because in the Torah the Lord said "Seven Weeks". This specific holy day came to be associated with the time that the Lord revealed himself to the children of Israel on top of mount Sinai, when he appeared at the top of the mountain in fire, and glory, and smoke.
Then Moses and the children of Israel heard his voice, the mountain trembled, and that culminated with the Lord writing his law on the tablets of stone, known as the Ten Commandments.
So this happened 1500 years before Yeshua came. So, when these first believers were gathered together in one place in acts chapter 2, because the day of Pentecost had come, this is what they were recalling. They were recalling how the God of Israel had revealed his glory to them at mount Sinai, giving them his law on the tablets of stone.
And while they were there, remembering this, suddenly, beloved ones, the same God that revealed himself at Sinai, manifest his glory again to them all, the glory comes into the room, the tables are shaking, the room is being violently shaken by the wind. And then the Spirit of God manifest himself in fire, just like they saw on top of mount Sinai. And this time, rather than writing his law on a tablet of stone, what happened was: the fulfillment of Jeremiah and Ezekiel came to pass, where the Lord wrote his law upon their hearts. Thus bringing to culmination this holy special day called Shavuot or Pentecost.