The descent of the Holy Spirit upon the Apostles fifty days after Pascha, marking the full revelation of the Holy Trinity and the beginning of the Church's mission in the world. During Vespers, special kneeling prayers are offered and the church is adorned with greenery. This feast celebrates the completion of Christ's saving work and the outpouring of the Holy Spirit upon all believers. From this day forward, the Sundays of the year are numbered from Pentecost, signifying the continual life and growth of the Church in the grace of the Spirit.

The central worship service of the Orthodox Church, celebrating the Eucharist (Holy Communion). Usually celebrated on Sundays and feast days, the Divine Liturgy consists of the Liturgy of the Word (scripture readings) and Liturgy of the Faithful (Eucharistic prayer and communion). The most common forms are the Liturgies of St. John Chrysostom and St. Basil the Great.

The joint commemoration of the two great apostles: Peter, the leader of the Twelve, and Paul, the Apostle to the Gentiles. Celebrated on June 29th after the Apostles' Fast, this feast honors both their ministries and their martyrdom in Rome. Though different in background, both were instrumental in establishing the early Church.

The evening prayer service of the Orthodox Church, traditionally celebrated at sunset. Vespers includes psalms, hymns, scripture readings, and incense. On Saturday evenings, Great Vespers is often combined with the Sunday Divine Liturgy. The service marks the end of the liturgical day and prepares the faithful for rest and reflection.

The fiery Old Testament prophet who defended monotheism against Baal worship and was taken up to heaven in a chariot of fire. Celebrated on July 20th, Prophet Elijah represents zealous faith and God's power over false gods. His appearance at the Transfiguration alongside Moses shows his continued importance in Christian revelation.

The "falling asleep" and assumption of the Virgin Mary into heaven. Preceded by a two-week fast, this feast on August 15th celebrates Mary's death and her bodily assumption. Orthodox theology teaches that Mary experienced death but was immediately raised and taken to heaven, where she intercedes for all Christians.

The ceremonial procession of the Holy Cross on August 1st, traditionally marking the beginning of the Dormition Fast. This feast involves carrying the Cross in procession for veneration and blessing. It serves as spiritual preparation for the Dormition feast and emphasizes the Cross as our protection and source of strength.