While many know that Pentecost was a Jewish feast, few know that one aspect of this celebration is the remembrance of Moses receiving the Ten Commandments.
Giving of the Law
The Catholic Encyclopedia explains, "Since the close of biblical times, an entirely new significance, never so much as hinted at in Scripture, has been attached by the Jews to the feast: the Pentecost is held to commemorate the giving of the Law on Mount Sinai, which, according to Exodus 19:1, took place on the fiftieth day after the departure from Egypt. This view, admitted by several Fathers of the Church...has passed into some modern Jewish Liturgical books, where the feast is described as "the day of the giving of the Law."
This adds a fascinating connection to the Christian celebration of Pentecost.
On Pentecost, God gave the Church the gift of the Holy Spirit, where a new law is written, not on tablets of stone, but in our hearts.
The prophet Jeremiah foretold of such a law.
But this is the covenant I will make with the house of Israel after those days—oracle of the Lord. I will place my law within them, and write it upon their hearts; I will be their God, and they shall be my people. They will no longer teach their friends and relatives, “Know the Lord!” Everyone, from least to greatest, shall know me—oracle of the Lord—for I will forgive their iniquity and no longer remember their sin.
The "new law" in no way erases the Ten Commandments, but it embeds them into our hearts, calling us to a new standard of living.
St. John Paul II further commented on this symbolism in his encyclical, Veritatis Splendor:
Saint Thomas was able to write that the New Law is the grace of the Holy Spirit given through faith in Christ. The external precepts also mentioned in the Gospel dispose one for this grace or produce its effects in one's life. Indeed, the New Law is not content to say what must be done, but also gives the power to "do what is true" (cf. Jn 3:21). Saint John Chrysostom likewise observed that the New Law was promulgated at the descent of the Holy Spirit from heaven on the day of Pentecost, and that the Apostles "did not come down from the mountain carrying, like Moses, tablets of stone in their hands; but they came down carrying the Holy Spirit in their hearts… having become by his grace a living law, a living book".
Come, Holy Spirit!

