2 - History of Pentecost 
 
The Godly Biblical Feasts of the Lord are for BOTH Jewish and Christian BELIEVERS and all people - but must be obeyed by Jews and Christians. The HOLY Day of Pentecost, which is celebrated fifty (50) days after Resurrection Sunday (aka Feast of First Fruits) as God tells us exactly how to do it in Levitcus 23:15-22, commemorates the descent of the Holy Spirit upon the Apostles and other followers of Jesus Christ while they were in Jerusalem celebrating the Feast of Weeks or Shavout (weeks in Hebrew), as described in the Acts of the Apostles (Acts 2:1–31).
 
Since its date depends on the date of Feast of First Fruits, Pentecost is a "moveable feast". (Eastern Christianity has it right. It is not a set date decided by the evil Catholic Church and Papacy but decided exactly by God in Leviticus 23.

Many Christian denominations celebrate this "Holiday of the Faith" - and if they don't, they should!!! But most of them get it wrong because the evil Catholic Church has changed the date to not agree with God's Biblical Feast calendar so as to confuse the masses, just as the AntiChrist likes to do.
 
The term Pentecost comes from the Greek Πεντηκοστή (Pentēkostē) meaning "fiftieth". It refers to the festival celebrated on the fiftieth day after Feast of First Fruits, also known as the "Feast of Weeks” or Shavout and the "Feast of 50 days" in rabbinic tradition. Shavout means "'weeks" because Leviticus 23 says we are to count 7 weeks from Feast of Firstfruits - which is always a Sunday and the day Jesus rose - which takes you to a Saturday and add a day to get you to a Sunday which is how Jews call it "weeks" and Christians call it "50 days." It is the same Feast day of the Lord - the 4th Feast of 7 God commands that we celebrate which all are such a gift to our souls. 
 
The Festival of Weeks is also called the Feast of Harvest in Exodus 23:16 and the day of First Fruits in Numbers 28:26, as Jews were to bring the very best of the first of their crops of the wheat harvest and barley harvest to the Lord.

In Exodus 34:22 it is called the "firstfruits of the wheat harvest." The date for the "Feast of Weeks" originally came the day after seven full weeks following the first harvest of grain. 
 
After the destruction of the Temple in 70 AD offerings could no longer be brought to the Temple and the focus of the festival shifted from agriculture to the giving of the law on Sinai. This did happen as the Scriptures tells us, but Jews and Satan wanted to distance themselves for what really happened on the Feast of Pentecost in Jerusalem in 30 AD when 3000 Jews were saved and anointed with the Holy Spirit and the Church started to spread rapidly.

Since 70 AD, it became a Jewish custom to gather at synagogue on this Feast day and read the Book of Ruth and Exodus Chapters 19 and 20. The Jews do not even realize how prophetic this is because the Book of Ruth foreshadows the Bride of Christ - the true Church!!! Exactly what the Book of Acts is all about.