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 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 gathering to honor the Theotokos on December 26th, the day after Christmas. This synaxis celebrates Mary's central role in the Incarnation and her continued intercession for the faithful. The service emphasizes her title as 'Theotokos' (God-Bearer) and her unique position as the bridge between humanity and divinity.

The first Christian martyr, one of the seven deacons chosen by the apostles. Celebrated on December 27th, Stephen was stoned to death after giving a powerful speech about Christ's fulfillment of Old Testament prophecy. His prayer for his persecutors' forgiveness echoes Christ's own words and inspired many conversions, including Paul's.

The circumcision of the infant Christ on the eighth day after His birth, as required by Jewish law. Celebrated on January 1st, this feast emphasizes Christ's full humanity and His submission to the Mosaic Law. It also commemorates the giving of the name "Jesus" (meaning "God saves") and is often combined with the feast of St. Basil the Great.

The Archbishop of Caesarea and one of the Three Holy Hierarchs, defender of Orthodox theology against Arianism. Celebrated on January 1st, Basil wrote the Divine Liturgy bearing his name and established principles of monasticism. His work on the Trinity and pastoral care shaped Orthodox theology and practice for centuries.