Pentecost, the birthday of the church, concludes the fifty day season of Easter. Its roots are in Judaism: originally a harvest festival, it came to be a celebration of the giving of the Law at Sinai. ”Pentecost” derives from the Greek ”pentekoste” – ”fifty". The Finnish "Helluntai" is derived from the Swedish "Helig Dag” – ”holy day". With Easter and Christmas, it is the heart of one of three great sequences in the church's year, and has been celebrated since the third century. The liturgical colour is red, and there are six candles on the altar. Its emblems are the dove and flames.

According to the second chapter of Acts, at the first Pentecost the apostles were filled with the Holy Spirit, in fulfilment of the promises of Jesus and the Old Testament prophets. As Peter preached, many were baptized and the church increased in number by about three thousand people. Everyone heard the message of salvation in their own language, underlining the call to unity and that the Gospel belongs to all nations. Pentecost established a new covenant between God and humanity.

Pentecost's significance is underlined by the fact that readings and prayers are also provided for its eve. It is followed by Pentecost week, when we reflect on the life-giving power of the Holy Spirit. The remaining Sundays of the year are designated ”Sundays after Pentecost”. With Pentecost the third main sequence of the church's year begins, which gives expression to the congregation's living witness of faith in the lives of its members, and to what it means to follow Christ in practice.