One of the biggest differences most Roman Catholics would see between the Roman rite and Byzantine rite is the way the Mass or as it is called in the Byzantine rite, Divine Liturgy, is celebrated.
The whole liturgy is sung or chanted with a continuous back and forth between the priest and the congregation. The priest wears different vestments and uses different-looking religious articles or vessels during the celebration of the liturgy. For most of the liturgy, the priest leads the congregation in worship by facing east or with his back to the people. However, there is much more movement of the priest between the sanctuary and the nave of the church than in the Roman rite. Also, there are very few parts of the liturgy in which the congregation does not have an active part.
The prayers of the Byzantine liturgy, with the exception of the Creed (said without the Filioque) and Our Father, are different than in the Roman rite. There are more litanies throughout the liturgy and many more signs of the cross. The two main liturgies used, the Liturgy of St. John Chrysostom and the Liturgy of St. Basil, are approximately 1,600 years old. The bread consecrated into the body of Christ is leavened bread instead of unleavened bread. This symbolizes that Christ is the leaven in our lives. The priest distributes the precious body and blood of our Lord that have been mixed together in the chalice by use of a spoon instead of placing an unleavened host in the hand or on the tongue as in the Roman rite.
In the Byzantine Catholic Church, the seven sacraments are administered in ways that are different than in the Roman Catholic Church. For instance, baptism is conferred by immersion rather than the sprinkling of water. All three sacraments of initiation — baptism, confirmation (called Chrismation in the Byzantine Rite), and holy Eucharist — are administered at the same time. Thus, infants or adults receive all three sacraments when they are brought into the church. The sacrament of reconciliation usually is administered in front of the “iconostasis” — or icon screen that separates the sanctuary from the nave of the church — instead of using a confessional box or room. The sacrament of the sick is administered not only when someone is gravely ill, but also to the entire congregation at the end of Divine Liturgy (Byzantine Catholic Mass) various Sundays throughout the year. Those of you who saw the movie, “My Big Fat Greek Wedding,” witnessed how the sacrament of marriage is celebrated in the Byzantine rite. There is a crowning ceremony and a sharing of the common cup. In fact, the priest, not the couple themselves as in the Roman rite, actually confers the sacrament. Holy orders is conferred by a bishop in a manner similar to the Roman rite. However, married men can be ordained to the diaconate and priesthood in the Byzantine rite. Bishops are selected from the celibate clergy.