Pentecost commemorates the descent of the Holy Spirit upon the Apostles. It celebrates the establishment of the Church through the preaching of the Apostles and the baptism of the thousands who on that day believed in the Gospel message of salvation through Jesus Christ. Pentecost is the culmination of the revelation of the Holy Trinity.
The icon of the Holy Trinity—the three angelic figures who appeared to Abraham—is placed in the center of the church. The church building is decorated with flowers and the green leaves of the summer to show that God's divine breath comes to renew all creation. Green vestments and coverings are also used.
All Orthodox churches worldwide celebrate the descent of the Holy Spirit with an extraordinary service called the Kneeling Prayers. In this service everyone makes a full prostration, touching their foreheads to the floor, while three sets of poetical prayers are read.
Pentecost is the occasion at which we celebrate both the founding of The Good Shepherd and the founding of the Church. We celebrate this with a shared lunch.