All Catholics are united by common doctrines and beliefs, but they often express them in different ways. In Eastern Christianity, theology is not viewed in the scholastic manner that it has often been in the West. Theology cannot be separated from spirituality; they are intimately joined and related. For example, because of the theological emphasis on the participation of the baptized in God’s divine life, even infants are chrismated (confirmed) and receive the Holy Eucharist from baptism onward.
The Blackwell Dictionary of Eastern Christianity summarizes Eastern Christian spirituality in this way:
From the earliest centuries, the Christian East has understood the practice of theology as primarily a personal communion with Ho Theos, the Father, through the Logos, Christ, in the Holy Spirit, an experience lived in the state of prayer.
Traditions, devotions, and the liturgical life are intertwined; they can be distinguished but never separated. Contemplation of the Triune God is the goal of life, the goal of theology, and the pinnacle of spirituality.
In Eastern Christianity there is an intense focus on the reality of divinization, the partaking of the divine nature of the Triune God. A passage from St. Irenaeus’s Against Heresies (c. 180) aptly captures this point:
For it was for this end that the Word of God was made man and he who was the Son of God became the Son of Man, that man, having been taken into the Word, and receiving adoption, might become son of God.
There is great emphasis on the belief that Christians are called “to become partakers of the divine nature” (2 Pet. 1:4), not just to be “saved” from sin. Those united to Christ in faith and by the sacraments truly do become filled with the supernatural life of the Triune God and do become true children of God.
Why It’s Important:
Knowledge of Eastern Catholicism (and Eastern Christianity in general) can be very helpful to the Catholic apologist, although that shouldn’t be the primary reason for gaining such knowledge. As the fictional conversation between Paul and Richard indicates, the reality of Eastern Catholicism can clear away many misconceptions and misunderstandings about Catholicism in general.
For example, the fact that married men are allowed to become priests in the Eastern Churches helps to do away with the notion that the Catholic Church has dogmatically declared that all priests must be celibate; it can help to demonstrate the difference between dogmas and disciplines.
Many people, including some Catholics, think the Christian world has always been made up of Catholics and Protestants, so it’s helpful to point out that prior to the Protestant Reformation, all Christians—Catholic, Orthodox, and Ancient Oriental—believed in the Real Presence, the sacramental forgiveness of sins, a priestly hierarchy, and veneration of the saints. Knowledge of Eastern Christianity, both Catholic and otherwise, can be invaluable when discussing Church history, doctrine, and practice.
Most importantly, the Eastern Churches show forth the authentic unity and diversity that is truly Catholic. Eastern Catholics are concrete evidence that the Catholic Church is not a monolithic and homogenous Western institution but an ancient, catholic, and worldwide communion of the faithful united by dogma, doctrine, and the See of Peter. In the beautiful words of the Catechism:
The rich variety of ecclesiastical disciplines, liturgical rites, and theological and spiritual heritages proper to the local churches unified in a common effort, shows all the more resplendently the catholicity of the undivided Church (CCC 835).
I am referring to the Church of Rome, the Eastern Orthodox churches, the Oriental Orthodox churches, the Polish National Catholic Church, The Old Catholic Union of Utrecht, the Ethiopian church, Mar Thoma, etc. etc. -- ALL OF WHICH are classified as Catholic no less than Methodists, Lutherans, and Baptists are classified as Protestant.
All of which are classified as Catholic? Hmmm.... could you please show evidence that these churches you listed are in "full communion" with the Bishop of Rome as the 23 Rites I mentioned are.