The Christian holiday of Pentecost is celebrated on the eighth Sunday after Easter. It is always on a Sunday and this year the day is June 23.
On Pentecost, the birthday of the Church of Christ is celebrated. On this day, the Lord Jesus Christ founded his church on earth by sending the Holy Spirit. According to biblical tradition, on the 50th day after Passover, Jerusalem was full of pilgrims who came for the great Jewish holiday dedicated to God's legislation on Mount Sinai.
The twelve apostles of Christ and the Mother of God were gathered for prayer in the house where 50 days ago they dined before Passover together with Jesus Christ. Suddenly there was a noise as if a strong wind had blown and filled the whole house, and flames resembling tongues of fire appeared above the heads of each of the praying men. The apostles were filled with the Holy Spirit and began to praise God in all the languages they did not know until then. The flames were the visible sign of the impact of the Holy Spirit on Christ's disciples, who were given the power to preach Christ's teaching to all nations. This is how the foundations of the Church were laid, which is why the feast of Pentecost is considered her birthday.
After this day, the apostles decreed that Christians commemorate this great event - the descent of the Holy Spirit - every year on this day. The Monday after Pentecost is the feast of the Holy Spirit. The Church established this holiday because of the greatness of the Most Holy and Life-Giving Spirit, through whom all wisdom is given to us and who is the source of life.
For the Old Testament, Pentecost was one of the three great feasts. Originally, the holiday marked the completion of the barley harvest. It was celebrated with an offering of bread and sacrificial animals as a day of joy and thanksgiving, recalling the wanderings in the desert and the deliverance from Egypt.
In later times this day commemorated the receiving of the Sinaitic legislation, fifty days after the Jews' exodus from Egypt. The holiday was solemn and joyful, a large number of people flocked to Jerusalem to offer thanks to God the sacrifice established by the law. I BGNES