Pentecost Pentecost, "the Fiftieth [day]")is a prominent feast in the calendar of Ancient Israel celebrating the giving of the Law on Sinai, and also later in the Christian liturgical year commemorating the descent of the Holy Spirit upon the remaining eleven disciples of Christ (Judas had hanged himself) after the Resurrection of Jesus. The feast is also called Whit Sunday, Whitsun, or Whit, especially in the United Kingdom, where the following Monday was traditionally a holiday. Pentecost is celebrated seven weeks (50 days) after Easter Sunday, hence its name. Pentecost falls on the tenth day after Ascension Thursday. Among Christians, Pentecost commemorates the descent of the Holy Spirit upon the Twelve apostles and other followers of Jesus as described in the Acts of the Apostles 2:1-31. For this reason, Pentecost is sometimes described as the "Birthday of the Church." The Pentecostal movement of Christianity derives its name from the New Testament event.