Galatians 3: 10 - 14 (NIV): 10 All who rely on observing the law are under a curse, for it is written: "Cursed is everyone who does not continue to do everything written in the Book of the Law." 11 Clearly no one is justified before God by the law, because, "The righteous will live by faith." 12 The law is not based on faith; on the contrary, "The man who does these things will live by them." 13 Christ redeemed us from the curse of the law by becoming a curse for us, for it is written: "Cursed is everyone who is hung on a tree." 14 He redeemed us in order that the blessing given to Abraham might come to the Gentiles through Christ Jesus, so that by faith we might receive the promise of the Spirit.
I knew Pentecost was called "The Feast of Weeks", but I didn't realize it was also called Shavout and is celebrated by Jews as the day God gave the Law to Moses on Mt. Horeb. Originally, it was a celebration of the first wheat harvest. It fell 50 days after Passover (Pentecost is Greek for "fifty"). Israelites would bring their first fruits to the Temple of God and celebrate his goodness. But during the Exile in Babylon in 605 B.C., Israelites began to celebrate the day, not so much for the first harvest, but because it was the very day God gave Moses the law. After all, they had lost their land and could no longer plant and harvest wheat crops.
The similarities between Mt. Horeb and Pentecost in Acts 2 are remarkable: On Mt. Horeb, there was a loud trumpet, smoke covered the mountain, the earth shook, and fire from God came down. At Pentecost there was the sound of a rushing wind, the earth shook and tongues of fire came down on those present. At Horeb, the people rebelled and created a golden calf. God punished them and "three thousand died that day." (Exodus 32: 35). At Pentecost, Peter preached and three thousand were saved.
The law brings a curse, Paul says, because we cannot fully keep it. It is faith that saves us and always has been. Jesus broke the curse and offers life for all who believe. Now we celebrate Pentecost as the day we received the gift of the Holy Spirit.