Pentecost is one of the principal feast days of Christianity. It commemorates the descent of the Holy Spirit onto Christ's apostles and marks the beginning of the Church's ministry. The Book of Acts describes the apostles as speaking in tongues on this day, becoming able to preach the gospel in many different languages. In some congregations, this is observed through scripture readings in different languages. The name is also applied to a Jewish festival, also known as the Feast of Weeks, because it is held seven weeks after Passover. Similarly, the Christian Pentecost, also known as Whit Sunday or Whitsun, is seven weeks after Easter.