Pentecost: the Holy Spirit is poured out
On the day of Pentecost the Holy Spirit came on the believers with a sound like a rushing wind and tongues like fire. They spoke in the languages of Jews gathered from across the world, Peter preached Christ crucified and risen, and about three thousand were baptized.
They were all filled with the Holy Spirit and began to speak with other languages, as the Spirit gave them the ability to speak.
Acts 2:4 (World English Bible)
Pilgrims from Parthia to Rome heard God's mighty works in their own languages (Acts 2:9–11). Peter explained that this was what Joel had foretold, that God would pour out his Spirit on all flesh, and that the Jesus they had crucified God had raised up and made both Lord and Christ (Acts 2:36). He called them to repent and be baptized in Jesus' name for the forgiveness of sins.
The new believers devoted themselves to the apostles' teaching, fellowship, the breaking of bread, and prayer (Acts 2:42). Fifty days after the Passover at which Christ died, the harvest feast of Pentecost became the birthday of the church.
Places
Dating notes
Ussher: 24 May AD 33, fifty days after the resurrection counted inclusively, a Sunday. It begins this era.