The celebration of Christ's birth in Bethlehem. The feast is preceded by a 40-day Nativity Fast and celebrated with the Divine Liturgy, special hymns like the Troparion of the Nativity, and the blessing of homes.

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 sacrament of initiation into the Orthodox Church, through which a person is united with Christ in His death and resurrection. The baptismal candidate is immersed three times in water in the name of the Father, Son, and Holy Spirit, dying to sin and rising to new life in Christ. Baptism cleanses from original sin, grants adoption as God's child, and makes the person a member of the Body of Christ. In Orthodox practice, baptism is immediately followed by chrismation and first communion.

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.

The 14th-century monk who founded the Trinity Lavra and renewed Russian monasticism. Celebrated on September 25th, Sergius established the monastery dedicated to the Trinity and inspired a spiritual revival in Russia. He blessed Prince Dmitri before the Battle of Kulikovo and represents the harmony between contemplative life and national service.

The Apostle and Evangelist John, author of the Fourth Gospel, three Epistles, and Revelation. Known as "the Theologian" for his profound spiritual insights and "the Beloved Disciple" for his closeness to Christ. Celebrated on May 8th, his feast honors his unique witness to Christ's divine nature and his care for the Theotokos.

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 commemoration of the Archangel Michael and all the bodiless powers (angels) on November 8th. This feast celebrates the angelic hierarchy and Michael's role as leader of God's army against evil. Orthodox tradition honors angels as God's messengers and guardians, with Michael being especially venerated as protector of the Church and individual Christians.

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.

A devotional service of praise consisting of hymns sung while standing ("akathist" means "not sitting"). The most famous is the Akathist to the Theotokos, traditionally sung during the fifth Friday of Great Lent. Akathists can honor Christ, the Theotokos, or various saints. These services are deeply moving expressions of Orthodox hymnography and devotion.

The missionary bishop who translated the liturgy and scriptures into native Alaskan languages. Celebrated on March 31st, Innocent (John Veniaminov) served as a priest and later bishop in Alaska and Siberia. He learned multiple native languages and created alphabets for languages that had none, earning him the title 'Apostle to America.'