According to the Book of the Apostles, on the 50th day of Easter known in the ancient Greek world as Pentecost, God sent his Holy Spirit upon the disciples. They had gathered in prayer and thanksgiving wondering when God would send them a clear vision for the church. On that Pentecost God sent the spirit upon the disciples, and the spirit appeared upon their heads like tongues of fire. This is the day we celebrate as the birth of the Christian Church and its mission to proclaim the good news to the whole world.