What Separates Catholics and Protestants?


Kenneth R. Samples

Article ID:



Jul 31, 2022


Apr 8, 2009

The full PDF can be viewed by following the link below the excerpt.


There are many areas of difference between Catholicism and evangelical Protestantism.25 These areas extend to both doctrines and practices, and range from very minor differences to those that can only be considered major points of contention. The following is just a brief list of the most consequential doctrinal differences between the two groups.26 These are areas in which Catholicism generally differs with virtually all of the specific denominations within evangelical Protestantism. These areas obviously overlap and have significant implications for further areas of theology and religious practice. We will briefly note the general concerns expressed by Protestants.

Catholics and Protestants- Authority

The question of authority is an area of central dispute between Catholics and Protestants. The Reformers referred to it as the formal cause of the Reformation. Catholics affirm a triad of authority: Scripture, apostolic tradition, and the teaching office of the church (magisterium). Implications of this authority system include: the Petrine doctrine (primacy of Peter), apostolic succession, papal supremacy and infallibility, and, as it relates to Scripture, the acceptance of the Apocrypha.

Protestants, by contrast, reject the Catholic system in favor of the Reformation principle of sola Scriptura (Scripture alone as the primary and absolute norm of doctrine). Sola Scriptura implies the authority, clarity, and sufficiency of Scripture, and uniquely gives Scripture alone the role of final arbiter in all matters of faith and morals.27

Evangelicals charge the Catholic church with affirming an illegitimate authority system and express great concern about Catholicism’s decision to: (1) place human traditions on par with God’s written Word, (2) grant infallibility to the church (magisterium), (3) subordinate the individual believer’s interpretation of Scripture to the magisterium, (4) affirm the primacy and infallibility of the pope, and (5) introduce noncanonical books into the canon (the Apocrypha). Evangelicals believe that Catholicism’s misguided authority structure has allowed numerous unbiblical teachings to arise in the church.

We will return for a more thorough discussion of this crucial issue of authority in Part Three of this series.

Catholics and Protestants- Justification

Also of central dispute between evangelicals and Catholics is the crucial soteriological doctrine of justification. The Reformers referred to this doctrine as the material cause of the Reformation. Although we can only summarize the views here, we will also return to this issue in Parts Three and Four.

Theologian and Reformation scholar Peter Toon summarizes the main features of the official Roman doctrine of justification:

1. Justification is both an event and a process. An unrighteous man becomes a righteous man. Becoming a child of God in baptism and having the remission of sins, the Christian is made righteous. (If during this process he should lose faith or fall away, he may be restored through the sacrament of penance.)

2. Justification occurs because of the “infusion” of the grace of God into the soul, whereby inherent righteousness becomes one of the soul’s characteristics.

3. This imparted, “infused” righteousness is described as the “formal cause” of justification. The “meritorious cause” is Christ’s passion and death.

4. The believer will only know for certain that he is justified at the end of the process. In the meantime, his constant duty is to co-operate with the grace of God given to him.28

Oxford theologian and internationally recognized authority on the Reformation doctrine of justification by faith, Alister McGrath, summarizes the Reformation Protestant position on justification:

1. Justification is the forensic [i.e., legal] declaration that the Christian is righteous, rather than the process by which he or she is made righteous. It involves a change in status rather than in nature.

2. A deliberate and systematic distinction is made between justification (the external act by which God declares the believer to be righteous) and sanctification or regeneration (the internal process of renewal by the Holy Spirit).

3. Justifying righteousness is the alien righteousness of Christ, imputed to the believer and external to him, not a righteousness that is inherent within him, located within him, or in any way belonging to him.

4. Justification takes place per fidem propter Christum [by faith on account of Christ], with faith being understood as the God-given means of justification and the merits of Christ the God-given foundation of justification.29

While the Protestant Reformers were essentially unified in their understanding of justification, modern-day evangelicalism is much less so.30 Nevertheless, today’s Reformation Protestants have consistently criticized the Catholic position for: (1) failing to recognize that justification is solely a judicial act of God that changes our status but not our state; (2) not making the necessary distinction between justification (being declared righteous) and sanctification (being made righteous); (3) interpreting justifying righteousness as infused and intrinsic, rather than imputed and extrinsic; (4) failing to see that assurance is a necessary byproduct of being justified; and (5) making justification a synergistic (man cooperating with God) process rather than a monergistic (God working alone) act.

Because Reformation Protestants see the doctrine of justification by faith as the very heart of the gospel, this dispute takes on extreme significance. While it is important to understand the nuanced doctrinal points described above, the issue of how one is justified before God is more than just an academic theological debate. Reformation Protestants believe that to confuse or compromise the doctrine of justification is to run the dangerous risk of obscuring the very gospel of Christ. Following the Reformers, today’s Reformation Protestants believe that the Catholic church’s soteriological system has actually placed obstacles in the way of Catholics entering in to an authentically saving relationship with Jesus Christ.

Catholics and Protestants- Mariology

It might rightly be said that evangelicals have a tendency to ignore Jesus’ mother Mary. Catholics, on the other hand, greatly exalt her. Such dogmas as the Immaculate Conception and bodily Assumption, coupled with such titles as “Queen of Heaven,” “Queen of all Saints,” and the “Immaculate Spouse of the Holy Spirit,” make Mary in the minds of Catholics the most exalted of all God’s creatures.

While Catholics propose Mary as a point of unity with other Christians, most evangelicals see Mariology as a formidable barrier between themselves and Catholics. Even evangelicals who are for the most part sympathetic to Catholicism generally view this element of Catholic belief as grossly unbiblical. One evangelical commission on evaluating Catholic Mariology stated: “We as evangelical Christians are deeply offended by Rome’s Marian dogmas because they cast a shadow upon the sufficiency of the intercession of Jesus Christ, lack all support from Scripture and detract from the worship which Christ alone deserves.”31 Although the documents of Vatican II inform us that Mary’s exalted role “neither take away from nor add anything to the dignity and efficacy of Christ the one Mediator,”32 most evangelicals believe Catholic Mariology actually undermines the foundation of orthodox Catholic Christology.

Catholics and Protestants- Sacramentalism and the Mass

Sacramentalism is a central and vital component within Catholic theology. For Catholics, sacraments are “effective signs” of grace instituted by Christ. Catholicism’s seven sacraments (baptism, confirmation, Eucharist, penance, extreme unction[last rites], holy orders[ordination into the priesthood], and matrimony) both signify grace and cause it to happen ex opere operato (“they work by their own working”).

While various evangelical denominations differ in their acceptance and approach to sacraments (or ordinances), generally speaking evangelicals differ with the Catholic view in number, nature, and operation of the sacraments. The Eucharist and the sacrificial nature of the mass in particular engender great dispute between Catholics and evangelicals. Both of these areas of concern have direct Christological implications.

Catholics and Protestants- Religious Pluralism

From the time of Cyprian until modern times, the Catholic church has affirmed the slogan extra ecclesiam nulla salus (no salvation outside the [visible body of the one institutional] church). Vatican II affirms, however, that salvation is “not only for Christians, but for all men of good will in whose hearts grace works in an unseen way.”33 These statements of Vatican II clearly opened the door for German theologian Karl Rahner’s “anonymous Christianity” — the belief in the possibility of salvation without explicit Christian faith, even through non-Christian religions.

While Catholic theology assures us that all the redeemed are ultimately saved through Christ alone, evangelicals are greatly concerned that these pluralistic trends greatly detract from the uniqueness of Christianity and open the Pandora’s box of universalism. In light of this pluralism, is there any necessary reason to consider becoming Catholic, or even Christian?

In Part Three of this series we will examine the issues of authority and justification in more detail.

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