What are some substantial differences between Roman Catholicism, Eastern Orthodoxy and Protestantism?

What are some substantial differences between Roman Catholicism, Eastern Orthodoxy and Protestantism?

This reply is rather long, and supplemental links more fully answer the question, (see http://peacebyjesus.net/eovs.rome.html which more directly answers this question) but there is much to this issue, and this reply may leave you better informed than some others.

First and mainly to be considered is the largest single church, Roman Catholicism, which is a religion that developed over time as a deformation of the NT church. It officially (if not all effectually) affirms valid Scripturally Truth (though not all) but progressively added mere traditions of men, these being distinctive Catholic beliefs (many of which are shared by the Eastern Orthodox) which are not manifest in the only wholly inspired substantive authoritative record of what the NT church believed (including how they understood the OT and gospels), which is Scripture, especially Acts thru Revelation.

For Catholicism exalted herself as the sure and supreme authority on faith and morals, effectively being superior over Scripture.

Pope Leo_xiii in Providentissimus Deus presumes,

“ Catholic doctrine, as authoritatively proposed by the Church, should be held as the supreme law; for, seeing that the same God is the author both of the Sacred Books and of the doctrine committed to the Church,” but which is a false premise. For the only substantive source of express public Divine revelation is Scripture. And both men and writings of God were being recognized as being so by common souls before a church presumed she was essential for this as conditionally incapable of error, which Catholicism does presume.

And rather than being subject to Scripture as supreme, Rome began to use the sword of men for ecclesiastical discipline and to achieve power (something early Protestantism, had to unlearn).

By the 4th century, we have a pope, Damasus 1, employing murderous thugs in order to secure his throne from his rival, and the beginning of the Caesario-papacy.

Eamon Duffy (Pontifical Historical Commission, Professor of the History of Christianity at the University of Cambridge, and former President of Magdalene College) reports:

Damasus’ grass-roots supporters included squads of the notoriously hard-boiled Roman fossores, and they massacred 137 followers of the rival Pope Ursinus in street-fighting that ended in a bloody siege of what is now the church of Santa Maria Maggiore...”

In addition, the conversion of Constantine, “propelled the bishops of Rome into the heart of the Roman establishment. Already powerful and influential men, they now became grandees on a par with the wealthiest senators in the city. Bishops all over the Roman world would now be expected to take on the role of judges, governors, great servants of state..” (Saints and Sinners,” New Haven and London: Yale University Press, 1997, 2001, pp. 37-38)

J. N. D. (1989 confirms the carnal means of the ascendancy of Damasus, and also records that he was,

indefatigable in promoting the Roman primacy, frequently referring to Rome as 'the apostolic see' and ruling that the test of a creed's orthodoxy was its endorsement by the Pope. In 378, he persuaded the government to recognize the holy see as a court of first instance and also of appeal for the Western episcopate... In tune with his ideas, Theodosius 1 (379-95) declared (February 27, 380) Christianity the state religion in that form…for Damasus this primacy was not based on decisions of synods, as were the claims of Constantinople, but exclusively on his [presumption of] being the direct successor of St. Peter...” Upon which false premise he presumed “judicial power to bind and loose, and the assurance of this infused all his rulings on church discipline. (Kelly, J. N. D. (1989). The Oxford Dictionary of Popes. USA: Oxford University Press. pp. 32,34)

This would later result in the the formal declaration of the novel and unScriptural premise of ensured perpetual papal infallibility by Vatican 1. For Rome has presumed to formally “infallibly” declare she is and will be perpetually infallible whenever she speaks in accordance with her (scope and subject-based) criteria, which renders her declaration that she is infallible, to be infallible, as well as all else she accordingly declares.

However, while men such as the manifest (2Co. 6:4–10) New Testament apostles could speak and write as wholly inspired of God, and also provide new public Divine revelation thereby - which Catholic “fathers” and popes and prelates did and do not do - Catholic researchers themselves, among others, provide testimony against the New Testament church even looking to Peter (a true apostle) himself as the first of a line of infallible popes reigning as the exalted head of the church from Rome.

**Klaus SchatzJesuit Father theologian, professor of church history at the St. George’s Philosophical and Theological School in Frankfurt] in his work, “Papal Primacy,” finds: “If one had asked a Christian in the year 100, 200, or even 300 whether the bishop of Rome was the head of all Christians, or whether there was a supreme bishop over all the other bishops and having the last word in questions affecting the whole Church, he or she would certainly have said no." **

Moreover, by teaching such things as “It follows that the Church is essentially an unequal society, that is, a society comprising two categories of per sons, the Pastors and the flock...the one duty of the multitude is to allow themselves to be led, and, like a docile flock, to follow the Pastors,” (Vehementer Nos, an Encyclical of Pope Pius X promulgated on February 11, 1906) then when leadership overall goes “South” then so do those who follow them, or they are left looking for salvation, versus finding that via Scripture, which never falls into immorality or false doctrine.

Being overall not grounded in this sure foundation, then as Cardinal Ratzinger observed, referring to the 14th century,

"For nearly half a century, the Church was split into two or three obediences that excommunicated one another, so that every Catholic lived under excommunication by one pope or another, and, in the last analysis, no one could say with certainty which of the contenders had right on his side. The Church no longer offered certainty of salvation; she had become questionable in her whole objective form--the true Church, the true pledge of salvation, had to be sought outside the institution.“ (Joseph Cardinal Ratzinger, head of the Sacred Congregation of the Doctrine of the Faith for the Church of Rome, “Principles of Catholic Theology,” trans. by Sister Mary Frances McCarthy, S.N.D. (San Francisco: Ignatius, 1989) p.196)

And presently Roman Catholics are part of a church which consists of different brands of Catholics, more so more so than in typical evangelical churches. The most extreme on the “right” are those who espouse the medieval Catholic position of implicit obedience to most everything the pope publicly teaches, but reject modern popes. And those who reject some of the modern Catholic teachings based upon their judgment of what valid church teaching consists of and means, and attack the present pope. As well as those who affirm that modern teaching is not in contradiction to historical Catholic teaching, which are clarifications of it, and are not be submitted and (at the least) not publicly objected to. Then there are the very liberal members such as publicly reject even modern Catholic moral positions. But all of whom (except the first class described) are manifestly considered, in life and in death, to be members in communion with “the Church.”

As for Eastern Orthodoxy, while typically less technical in its theology, and somewhat prone to appeal to mysticism, as said, they hold to many of the same distinctive beliefs which are not not manifest in the only wholly inspired substantive authoritative record of what the NT church believed, including subscribing to the premise that the church is the supreme sure standard for what is of God:

It is the Church that tells us what is Scripture, and it is also the Church that tells us how Scripture is to be understood...The decisive test and criterion for our understanding of what the Scripture means is the mind of the Church (http://orthodoxinfo.com/phronema/ware_howto.aspx)

However, while it is true that as seen in Acts 15, magisterial church office is to be the supreme authority in determining what it is to be taught, and as the Westminster Confession states, “It belongs to synods and councils, ministerially to determine controversies of faith..and authoritatively to determine the same; which decrees and determinations, if consonant to the Word of God, are to be received with reverence and submission,” (Chapter XXXI) the issue is that of the sure infallible status that Catholicism ascribes to its magisterial church office in formally teaching by her ecumenical councils on faith and morals for the whole church.

Which is never seen or promised (or necessary in Scripture. Instead, contrary to the premise that being the magisterial authority over the cooperate body from which Scripture came, and which affirms what it is, means that it possesses ensured infallibility, the reality is that the church actually began in dissent from those who sat in the seat of Moses over Israel, (Mt. 23:2) who were the historical instruments and stewards of Scripture, "because that unto them were committed the oracles of God," (Rm. 3:2) to whom pertaineth" the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises" (Rm. 9:4) of Divine guidance, presence and perpetuation as they believed, (Gn. 12:2,3; 17:4,7,8; Ex. 19:5; Lv. 10:11; Dt. 4:31; 17:8-13; Ps, 11:4,9; Is. 41:10, Ps. 89:33,34; Jer. 7:23)

And instead they followed an itinerant Preacher (as far as those who sat in the seat of Moses was concerned) whom the historical magisterium rejected, and whom the Messiah reproved by Scripture as being supreme, (Mk. 7:2-16) and established His Truth claims upon scriptural substantiation in word and in power, as did the early church as it began upon this basis. (Mt. 22:23-45; Lk. 24:27,44; Jn. 5:36,39; Acts 2:14-35; 4:33; 5:12; 15:6-21;17:2,11; 18:28; 28:23; Rm. 15:19; 2Cor. 12:12, etc.)

And despite both Roman Catholicism and Eastern Orthodox both laying claim to the title “Catholic” and as being the One True Apostolic Church, after over 1,000 years they remain divided due to irreconcilable differences. (see EO_vs_Rome)

The Orthodox Church opposes the Roman doctrines of universal papal jurisdiction, papal infallibility, purgatory, and the Immaculate Conception precisely because they are untraditional." (Orthodox apologist and author Clark Carlton: THE WAY: What Every Protestant Should Know About the Orthodox Church, 1997, p 135)

The East never accepted the regular jurisdiction of Rome, nor did it submit to the judgment of Western bishops. Its appeals to Rome for help were not connected with a recognition of the principle of Roman jurisdiction but were based on the view that Rome had the same truth, the same good. (Roman Catholic theologian Yves Congar, Diversity and Communion (Mystic: Twenty-Third, 1982), p. 26)

Roman Catholicism, unable to show a continuity of faith and in order to justify new doctrine, erected in the last century, a theory of "doctrinal development."…On this basis, theories such as the dogmas of "papal infallibility" and "the immaculate conception" of the Virgin Mary (about which we will say more) are justifiably presented to the Faithful as necessary to their salvation. (http://www.ocf.org/OrthodoxPage/reading/ortho_cath.html)

Finally we have Protestantism, but which as typically defined is far too diverse to be meaningful, often encompassing everything from evangelical Christian churches to so-called “Christian science” to Swedenborgism. Therefore it cannot be critically examined as one single church. However, based upon its most basic distinctive, that of Scripture being the sure and supreme sufficient standard for faith and morals, as the wholly God-inspired word of God, with its basically literal hermeneutic, then its members attest to being both the most strongly unified major religious group in many core beliefs as well as being a diverse community.

And rather than adopting such unScriptural Catholics beliefs, from prayer to created beings in Heaven, including the virtual worship of its unScriptural Mary by many Catholics, to her mistaken belief in the Lord’s supper, to compelled clerical celibacy, evangelical Bible faith overall tends to be more Scriptural (with some exceptions such as women pastors).

However, the prophesied overall later-day spiritual declension of the church is being seen today, first by lessened commitment to Scripture and its integrity.

And while Catholicism presumes too much of an office and thereby what it promulgates, and to the expense of the authority of Scripture, evangelicalism presumes too much of Scripture as far as practical authority is concerned, and too little of the magisterial office established thereby, as mentioned before

In addition, while Scripture requires separation from false believers, (1 Corinthians 5:9; 2 Corinthians 6:14–18) and dissent from corrupt tyrannical authority when the latter is contrary to the word of God (Acts 4:19) and rejects those who validly dissent (which again, is how the NT church began), yet in Protestantism this too much became the standard recourse in dealing with differences, and fails to pursue a central magisterium. The fact that the church of Rome has effectively rendered that as something to be avoided, in principle a central magisterium of Godly men is Scriptural.

The basic unity of the NT church church was under men of supreme Scriptural integrity, "not walking in craftiness, nor handling the word of God deceitfully; but by manifestation of the truth commending ourselves to every man's conscience in the sight of God. (2 Co. 4:2) And who, unlike what is typically seen today, could say that they, "in all things approving ourselves as the ministers of God..." (2 Co. 6:4)

In stripes, in imprisonments, in tumults, in labours, in watchings, in fastings; By pureness, by knowledge, by longsuffering, by kindness, by the Holy Ghost, by love unfeigned, By the word of truth, by the power of God, by the armour of righteousness on the right hand and on the left, (2 Corinthians 6:5-7)

And today Christianity (and I) fail of the degree of holiness and faith the prima NT church exampled and is needed for the church of the living God to manifest itself as being so, and as grounded in and supporting the Truth.

And besides Catholicism, the rest of what is called Protestantism fails more , being liberal.

However, God does not change, and Scripture is His sure established word, and teaches the way of salvation. In which the redeemed have come to God as souls damned by their works of sin - not saved because of works - and as destitute of any means or merit whereby they may escape their just and eternal punishment in Hell Fire and gain eternal life with God.

But who, with contrite heart have cast their whole-hearted repentant faith upon the mercy of God in Christ, trusting the risen Divine Lord Jesus to save them by His sinless shed blood. (Rm. 3:9 - 5:1) And whose faith is thus counted as righteousness, but it is a faith that will follow Him, being baptized under water and led by the Spirit of Christ in living according to the word of God (and repenting when convicted by conscience of not doing so).

To God be the glory in Jesus Christ.