This is not an issue of "ownership", it is an issue of demonstrable doctrinal continuity. The Early Church Fathers preached a form of Christianity and Liturgy that more closely resembles modern Catholicism than any other form of Christianity or denominational doctrine. That form of Christianity was embodied in the Traditions and Creeds that preceded and produced the Canon of Scripture. The Church does not spend time extracting snippets and quotes attempting to prove that they were like us, we have spent the last 2,000 years ensuring that we remain like them.
Peace be with you.
If it is not an issue of "ownership", then why the outrage and guffaws whenever a non-Catholic Christian uses the words and thoughts of some of those ECFs? You must know that the Reformers moved as they did because the Church of Rome had turned away from the orthodox faith in many, demonstrable ways and when we here use the quotations from those ECFs to prove the changes that have occurred over the centuries, we are criticized and condemned for "taking them out of context" or misunderstanding or misstating them. Yet, over and over again - just as those Reformers did - we can prove the very contentions we make. I strongly disagree that the Roman Catholic Church has remained consistent with the orthodox Christian faith for the past 2000 years and that WAS the point the Reformers made.
Probably the biggest - and the most important one - was the doctrine of justification by faith without works - sola fide. The claim is usually made that nobody advocated for justification by faith alone before the Reformation, that no ECF ever taught that we are saved by faith apart from works. We know, however, from the very writings of those early theologians that they understood that very basic of Scriptural doctrines. Were there disagreements among some over the extent of justification versus sanctification? Yes, just as there have been disagreements over many of the interpretations of the other tenets of the Christian faith, but, rather than just rely upon these early believers to explain Scriptural doctrines, we should let Scripture interpret Scripture. Let Paul explain Luke and Mark and let Matthew and John explain Paul or Peter or James. What makes these ECFs any more qualified to explain Scriptural truths decades or centuries removed from the actual dates of the Biblical writings than the Apostles who were THERE and contemporaries of those other writers?
An interesting explanation is given at http://triablogue.blogspot.com/2009/12/seeds-of-reformation.html:
"Every major tenet of the Reformation had considerable support in the catholic tradition. That was eminently true of the central Reformation teaching of justification by faith alone….That the ground of our salvation is the unearned favor of God in Christ, and that all we need do to obtain it is to trust that favor – this was the confession of great catholic saints and teachers….Rome’s reactions [to the Protestant reformers] were the doctrinal decrees of the Council of Trent and the Roman Catechism based upon those decrees. In these decrees, the Council of Trent selected and elevated to official status the notion of justification by faith plus works, which was only one of the doctrines of justification in the medieval theologians and ancient fathers. When the reformers attacked this notion in the name of the doctrine of justification by faith alone – a doctrine also attested to by some medieval theologians and ancient fathers – Rome reacted by canonizing one trend in preference to all the others. What had previously been permitted also (justification by faith alone), now became forbidden. In condemning the Protestant Reformation, the Council of Trent condemned part of its own catholic tradition.” (RRC, 49, 51-52)
James Swan quotes the following from another book Pelikan wrote, one that I haven't read:
"Existing side by side in pre-Reformation theology were several ways of interpreting the righteousness of God and the act of justification. They ranged from strongly moralistic views that seemed to equate justification with moral renewal to ultra-forensic views, which saw justification as a 'nude imputation' that seemed possible apart from Christ, by an arbitrary decree of God. Between these extremes were many combinations; and though certain views predominated in late nominalism, it is not possible even there to speak of a single doctrine of justification."
Many other scholars have made comments similar to Pelikan's. One of the best brief overviews of this subject that I've seen is Nick Needham's chapter in JIP, 25-53. Needham makes many points relevant to this post, including the following:
"The language of justification occurs reasonably often in the fathers. What does the language mean? Although it does not always have the same precise connotation, it seems clear that there is a very prominent strand of usage in which it has a basically forensic meaning....The forensic framework of this justification language is further illustrated by another strand of patristic teaching that employs the concept of imputation - reckoning or crediting something to someone's account, a synthesis of legal and financial metaphors, where the books that are being kept are 'judgment books.'" (27-28, 32)
Additional ECF teachings are discussed at this link. I hope you will take a few minutes and read it. But with the issue of who is the true representative of the form of Christianity taught in Holy Scripture given to us by God, it should be those very Scriptures which stand as witness and not necessarily who did what within their own cultural and traditional communities. With the question of justification and righteousness being an infused or imputed righteousness, I believe the Scriptures DO settle that question most clearly.
I hope you have a good night.