Pentecost was the day when the Ten commandments were given to Moses. In the Old Testament, it was the birthday of Torah being presented to Israelites. In the New Testament, on this very same day, the Holy Spirit descended on the disciples and this marks the birthday of the Church.
There are 7 major annual Jewish Festivals. Out of these 7 festivals, four festivals fulfilled through the life of Jesus and they are recorded in the first five books of the New Testament. Let us see how these festivals relate to a Christian and how they were fulfilled in the life of Jesus
1. Passover - The day God passed over the Israelites and smote the Egyptians and enabled the Israelites to leave Egypt. Jesus did the very same thing on the cross for us
2. Unleavened bread - Jesus is our passover unleavened bread who died for us
3. First Fruits - The day when Jesus rose up from the dead.
4. Pentecost - 50 days from passover. The day when Holy spirit poured himself on his disciples.
The last 3 festivals are connected to the return of our Lord and I am not getting into an Eschatological drive here
5. Trumpets
6. Atonement and
7. Tabernacles
6. Atonement and
7. Tabernacles
So Yes! Pentecost means 50 and it is the birthday of the Church.