It wasn’t part of a question, but I think it is amazing to understand more of the significance of the “why pentecost?” I think many christians are under the false impression that this 50th day was a new holiday (holy day) formed by christianity because of the significance of the spirit creating the “birthday of the church” as some have called it. In fact it dates back to Exodus and Leviticus and was long part of God’s design.
The following is from Judaism 101:
Significance: Remembers the giving of the Torah; also a harvest festival
Observances: Studying Torah
Length: 2 days (Some: 1 day)
Customs: Eating dairy foods
You shall count for yourselves — from the day after the Shabbat, from the day when you bring the Omer of the waving — seven Shabbats, they shall be complete. Until the day after the seventh sabbath you shall count, fifty days… You shall convoke on this very day — there shall be a holy convocation for yourselves — you shall do no laborious work; it is an eternal decree in your dwelling places for your generations. -Leviticus 21:15-16, 21
Shavu’ot, the Festival of Weeks, is the second of the three major festivals with both historical and agricultural significance (the other two are Passover and Sukkot). Agriculturally, it commemorates the time when the first fruits were harvested and brought to the Temple, and is known as Hag ha-Bikkurim (the Festival of the First Fruits). Historically, it celebrates the giving of the Torah at Mount Sinai, and is also known as Hag Matan Torateinu (the Festival of the Giving of Our Torah).
The period from Passover to Shavu’ot is a time of great anticipation. We count each of the days from the second day of Passover to the day before Shavu’ot, 49 days or 7 full weeks, hence the name of the festival. See The Counting of the Omer. The counting reminds us of the important connection between Passover and Shavu’ot: Passover freed us physically from bondage, but the giving of the Torah on Shavu’ot redeemed us spiritually from our bondage to idolatry and immorality. Shavu’ot is also known as Pentecost, because it falls on the 50th day; however, Shavu’ot has no particular similarity to the Christian holiday of Pentecost, which occurs 50 days after their Spring holiday.
It is noteworthy that the holiday is called the time of the giving of the Torah, rather than the time of the receiving of the Torah. The sages point out that we are constantly in the process of receiving the Torah, that we receive it every day, but it was first given at this time. Thus it is the giving, not the receiving, that makes this holiday significant.
While the authors of jewfaq.org may not recognize a particular similarity, I think the message of picking this day for the coming of the Holy Spirit screams to us. We are the first fruits! On passover, Christ, the lamb, freed us from spiritual bondage and 50 days later the spirit came to redeem us from our physical limitations to obey – marking us and buying us for the Father for all time. It was a day of the giving of the spirit, which, in turn, immediately caused those receiving to “give witness” to others.
Understanding the old testament, not just the stories, but digging deeper to understand how the feasts and festivals, prescribed by the law, were celebrated and the meaning they held, is so amazing. Everything in the bible points to Christ. Sometimes we need to look a little deeper to see the treasure that is revealed in further study.