Pentecost is significant in both the Old and New Testaments. “Pentecost” is actually the Greek name for a festival known in the Old Testament as the Feast of Weeks (Leviticus 23:15; Deuteronomy 16:9). The Greek word means “fifty” and refers to the fifty days that have elapsed since the wave offering of Passover. The Feast of Weeks celebrated the end of the grain harvest.