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 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 sacrament of sealing with the Holy Spirit, administered immediately after baptism in the Orthodox Church. The priest anoints the newly baptized with holy chrism (myrrh) on the forehead, eyes, nostrils, ears, lips, chest, hands, and feet, saying "The seal of the gift of the Holy Spirit." This sacrament completes baptism and grants the fullness of the Holy Spirit, enabling the person to participate fully in the life of the Church. It corresponds to the Western sacrament of Confirmation but is given to infants.

The sacrament of marriage, uniting a man and woman in lifelong union blessed by God. The Orthodox wedding service consists of two parts: the Betrothal (exchange of rings) and the Crowning (placement of crowns on the couple's heads). The crowns symbolize both the glory and martyrdom of marriage, as well as the couple's status as king and queen of their domestic church. The couple drinks from the common cup and processes around the analogion three times. Marriage is understood as an icon of Christ's union with the Church.

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 joint commemoration of the two great apostles: Peter, the leader of the Twelve, and Paul, the Apostle to the Gentiles. Celebrated on June 29th after the Apostles' Fast, this feast honors both their ministries and their martyrdom in Rome. Though different in background, both were instrumental in establishing the early Church.