Pentecost is unique among traditional Christian holy days. It is a day shared by Jews and mainstream Christian churches. Jews who keep the Old Testament holy days may know it as the Feast of Weeks (Exodus 34:22, Deuteronomy 16:9-11) - that is what it is called in the books of Moses - but it is the same day, different name, as Pentecost (Acts 2:1-4). No other day I know of is shared by both Jews and mainstream Christianity.
Pentecost has deep meaning, which most churches only partially understand and Jews understand hardly at all. Yet when fully understood, Pentecost helps to reveal mysteries that many religious people have puzzled over for centuries.
Why does God allow so much suffering in the world?
If God is good, would He not want to prevent it? If He is all powerful, would He not be able to prevent it?
Why have so few in human history heard the only gospel by which they may be saved? The Bible is clear that only by the name of Christ and through the true gospel can anyone be saved, yet billions through circumstances of birth over which they have had no control have lived and died without an opportunity to hear the gospel and be saved, either because the gospel was not widely available in their country in their day or because they lived and died before Christ was even born.
Are they permanently lost because of when and where they were born?
On a personal level, if you have a loved one who has died without ever believing in God, is he or she lost forever? The answer from the Bible is, not necessarily.
There is still hope for the billions who have never been converted in this life, either because they never heard the true gospel or because their minds were never opened to be able to receive it.
Many atheists and agnostics reject religion altogether because of the contradictions taught by some churches that say that a God of love has condemned billions to hellfire for not believing a gospel they never heard.
Perhaps you know someone like that. You may have brother, sister, husband, wife, son, or daughter that rejects your religion because he or she feels it makes no sense.
But God has a great plan to save the majority of mankind regardless of when and where they lived. God's annual feasts and holy days, all of them, represent God's plan for the salvation of mankind, in stages. Each represents an important step.
Pentecost is a key.
The online article, The Secret Meaning of Pentecost, explains what many mainstream, traditional Christians do not know about this holy day of God. They understand that Pentecost represents the coming of God's Holy Spirit and the start of the New Testament Church, and it certainly represents that. But there is much more meaning in Pentecost than this. To properly understand the full meaning of Pentecost, it is important to understand how it fits into the whole plan of God and what that plan is.
It all has to do with the concept of "first fruits".
Ask yourself, if Pentecost represents first fruits, who are the second fruits, the main harvest?
Here is a link to the article:
http://www.meaningofpentecost.org/