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.

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.