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. Most interesting, however, is its use in Joel and Acts. Looking back to Joel’s prophecy (Joel 2:28–32) and forward to the promise of the Holy Spirit in Christ’s last words on earth before His ascension into heaven (Acts 1:8), Pentecost signals the beginning of the church age.