For the Jews in Jesus’ time and today, Pentecost was a celebration of Moses receiving the Ten Commandments on Mt. Sinai, which was thought to have happened 50 days after Passover. So for centuries, it was a holiday that celebrated the Law. But then, on the same day, God gave His people the Holy Spirit, making it also a holiday celebrating the Gospel.
See 10 Things You Should Know About Pentecost Sunday.
Have a merry Pentecost on Sunday!