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 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.

Brief prayer services traditionally celebrated at specific times of day: First Hour (6 AM), Third Hour (9 AM), Sixth Hour (noon), and Ninth Hour (3 PM). Each Hour includes psalms, troparia, and prayers appropriate to that time of day. These services sanctify the day and connect us to Christ's Passion, as they commemorate specific moments in His crucifixion and death.

A lengthy service combining Vespers and Matins, traditionally celebrated on the eve of Sundays and major feasts. The All-Night Vigil includes the singing of "Lord, I Call," the Magnificat, the Great Doxology, and numerous psalms and hymns. This service prepares the faithful spiritually for the upcoming feast.