The Feast of Pentecost crowns the Paschal cycle. In Greek, “Pentecost” means fifty, and thus, it names the Feast that comes 50 days or 7 weeks after Easter Sunday. The two great feasts which bookend Paschaltide, Easter and Pentecost, correspond to two Jewish feast days found in the Old Testament, namely Passover and Pentecost. 

Pope St. Leo the Great, in a sermon on Pentecost, compared the New Testament feasts with their Old Testament equivalents: “As once to the Hebrew people, freed from Egypt, the law was given on Mt. Sinai on the fiftieth day after the sacrifice of the lamb, so after the Passion of the Christ when the true Lamb of God was killed, on the fiftieth day from His Resurrection, the Holy Spirit came down on the apostles and the community of believers.”

In the Old Testament, Pentecost was the day on which God gave Israel the Torah (the Law) and they became a nation committed to serving Him. In the New Testament, Pentecost is the day on which the Holy Spirit descends on the Apostles as Christ promised to “teach you all things.” Dom Gueranger comments that “the Pasch, with all its triumphant joys, belongs to the Son of God, the Conqueror of death: Pentecost belongs to the Holy Spirit, for it is the day whereon He began His mission into this world, which, henceforward, was to be under His Law.”