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.

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.

The commemoration of the Virgin Mary's miraculous appearance in Constantinople, when she spread her veil over the praying Christians to protect them from enemies. Celebrated on October 1st, this feast is especially beloved in Slavic Orthodox churches. It emphasizes the Theotokos's continuing intercession and protection of the faithful.

The spiritual fathers of Optina Monastery who renewed Russian monasticism and spiritual direction. Celebrated on October 11th, these elders (including Sts. Moses, Anthony, Hilarion, Macarius, and Ambrose) guided thousands of pilgrims from all walks of life. Writers like Dostoevsky and Tolstoy sought their counsel. They represent the flowering of Orthodox spiritual guidance in 19th century Russia.

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 physician and evangelist who wrote the Gospel of Luke and Acts of the Apostles. Celebrated on October 18th, Luke was a companion of Paul and is patron of doctors and artists. His Gospel emphasizes Christ's compassion for the poor and outcast. He's traditionally credited with painting the first icon of the Theotokos.

A miraculous icon of the Theotokos known for comforting the afflicted and healing the sick. Celebrated on November 6th, this icon shows the Virgin Mary surrounded by angels distributing aid to various people in distress. Many miracles have been attributed to prayer before this icon, especially healing from illness and comfort in grief.

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.