Today the Greek Orthodox Church and worshippers celebrate the Feast of Pentecost, which is always celebrated 50 days after the Resurrection of Christ. At Pentecost, the disciples received the Holy Spirit as tongues of fire, fulfilling the promise that Christ had given them while He was still with them. This spirit was the Comforter who would lead them into the fullness of the Truth concerning God and would be for them their final preparatory gift from God for their ministry.
In the Church’s annual liturgical cycle, Pentecost is “the last and great day.” It is the celebration by the Church of the coming of the Holy Spirit as the end—the achievement and fulfillment—of the entire history of salvation. For the same reason, however, it is also the celebration of the beginning: it is the “birthday” of the Church as the presence among us of the Holy Spirit, of the new life in Christ, of grace, knowledge, adoption to God and holiness.
Pentecost in Greek means fifty, and in the sacred biblical symbolism of numbers, the number fifty symbolises both the fulness of time and that which is beyond time: the Kingdom of God itself. It symbolises the fulness of time by its first component: 49, which is the fulness of seven (7 x 7): the number of time. And, it symbolises that which is beyond time by its second component: 49 + 1, this one being the new day, the “day without evening” of God’s eternal Kingdom.