At the Jewish feast of Pentecost, or Harvest, celebrated fifty days after the Passover and thus Jesus’s death, his disciples were celebrating together when, as Luke records in Acts 2, the house was filled with a sound of rushing wind and fire appeared to rest on their heads. They were filled with the Holy Spirit and began speaking in other languages they had not previously known. The unusual event drew large crowds, to whom Peter and the disciples preached the gospel of Jesus’s death and resurrection. Thousands of people in Jerusalem were converted and baptised, and the church began to expand rapidly throughout Judea. This sending of the Holy Spirit upon the church marked a new epoch in God’s redemptive work and is spoken of by the apostles as a ‘guarantee’ of all eschatological promises in Christ (Ephesians 1:14).