How do Catholics and Protestants differ?

What the Bible says

Catholics and Protestants both confess the Apostles' and Nicene Creeds: one God as Father, Son and Holy Spirit; Jesus as truly God and truly man, who died for our sins, rose bodily, and will return.

There is one body and one Spirit, just as you were called to one hope when you were called; one Lord, one faith, one baptism

Eph 4:4-5

They parted over a handful of questions.

Where does authority lie? Protestants hold that Scripture, as God's word, is the final norm for faith and life (sola scriptura). They point to this.

All Scripture is God-breathed and is useful for instruction, for conviction, for correction, and for training in righteousness

2 Tim 3:16

Catholics teach that Scripture and sacred tradition flow from one revelation, and that the pope and bishops (the magisterium) are charged with interpreting it faithfully. They cite Paul's call to "cling to the traditions we taught you" (2 Thess 2:15) and his description of the church as "the pillar and foundation of the truth" (1 Tim 3:15). The canon differs too: Catholic Bibles have 73 books, Protestant ones 66.

Who is the pope? Catholics believe the bishop of Rome is Peter's successor and head of the whole church, and in 1870 the First Vatican Council defined that the pope is preserved from error when he formally defines faith or morals. The key text is this.

And I tell you that you are Peter, and on this rock I will build My church, and the gates of Hades will not prevail against it.

Matt 16:18

Protestants have traditionally read the rock as Peter's confession or as Christ; many Protestant scholars now accept that it is Peter but deny that his role passes to Rome's bishops.

How are we saved? Protestants stress that sinners are declared righteous before God by grace through faith, not by works.

For it is by grace you have been saved through faith, and this not from yourselves; it is the gift of God, not by works, so that no one can boast.

Eph 2:8-9

Catholics also teach that salvation is a gift of grace, but describe justification as including an inner renewal along with forgiveness, and speak of faith working through love in cooperation with grace. They often cite James.

As you can see, a man is justified by his deeds and not by faith alone.

James 2:24

Protestants read James as saying that a living faith produces deeds.

How many sacraments? Catholics and the Orthodox count seven, adding confirmation, reconciliation, anointing of the sick, ordination and marriage. Most Protestants keep the two Jesus himself instituted, baptism and the Lord's Supper. On the Supper, Catholics teach that bread and wine become Christ's body and blood in substance; Lutherans hold that Christ is truly present with the elements; the Reformed speak of a spiritual presence; many Baptist and evangelical churches see a memorial. See What are baptism and the Lord's Supper?.

Mary and the saints. Both honour Mary, who said, "From now on all generations will call me blessed" (Luke 1:48). Catholics add the doctrines of the Immaculate Conception (1854) and the Assumption (1950), and ask Mary and the saints to pray for them. Protestants find no clear biblical basis for these doctrines and fear that such prayers dim the place of Christ.

For there is one God, and there is one mediator between God and men, the man Christ Jesus

1 Tim 2:5

Catholics do not deny this. They say that asking a saint to pray is like asking a living friend, since we are surrounded by "a great cloud of witnesses" (Heb 12:1), and that honour for Mary differs from the worship due to God.

The church's witness

East and West parted in 1054, and Luther's protest in 1517 began the Reformation. The Lutheran Augsburg Confession (1530) confessed that people are freely justified for Christ's sake through faith The Augsburg Confession. The Council of Trent's decree on justification (1547) taught that justification includes inner renewal as well as forgiveness, and condemned the teaching it opposed Council of Trent, Decree on Justification.

In 1999 the Lutheran World Federation and the Catholic Church signed the Joint Declaration on the Doctrine of Justification. It confesses together that we are accepted by God by grace alone, in faith in Christ, and not because of our merit. It adds that the sixteenth-century condemnations do not apply to the teaching it sets out. The World Methodist Council (2006) and the World Communion of Reformed Churches (2017) later affirmed it, and the Anglican Communion welcomed its substance Joint Declaration on the Doctrine of Justification (1999).

The Fathers did not read Matthew 16:18 with one voice. Chrysostom says: "That is, On this faith and confession I will build my Church" Chrysostom. Augustine first took Peter as the rock, later Christ whom Peter confessed, and concludes: "Let the reader choose whether of these two opinions seems to him the more probable" Augustine. A medieval gloss reads it another way: Peter was made head of the apostles "that the Church might have one principal Vicar of Christ" Gloss, from Anselm.

On Romans 3:28 Matthew Henry gives the Protestant view: "the way of justification by faith for ever shuts out boasting." Yet he adds that "faith is a law, it is a working grace, wherever it is in truth" Matthew Henry.

In the original languages

In Matthew 16:18, "Peter" is Petros (Πέτρος) and "rock" is petra (πέτρα). The two forms differ, and some argue from this that the rock is not Peter. Others answer that in Aramaic, which Jesus probably spoke, the two were the same word, Cephas (John 1:42).

"To justify" is dikaioō (δικαιόω). It often has a courtroom sense, "to declare righteous," and Protestants lean on that. Catholics hold that Scripture never separates God's declaring from his renewing work (Titus 3:5-7).

Common objections

"Catholics add to the Bible and worship Mary." It is true that doctrines such as the Immaculate Conception are not written in Scripture; Catholics hold that they belong to the one revelation handed on in Scripture and tradition. Official teaching does not call for worship of Mary but honours her as one who leads to Christ, though Catholic voices admit that popular devotion can blur the line. It is fairest to judge a church by what it officially teaches.

"Protestants interpret the Bible however they like, and so they split into countless groups." The divisions are real and painful. Protestants reply that sola scriptura does not mean rejecting tradition, since they honour the creeds and confessions. On the history, see Why are there so many churches and denominations?.

"Catholics teach salvation by works, and Protestants by faith." This makes both sides simpler than they are. As the Joint Declaration shows, both agree that salvation begins in grace. Protestants say true faith bears good works (Eph 2:10); Catholics say good works are a response made possible by grace. Differences remain over how justification relates to renewal, and over merit and assurance.

Going further

In Korea, Catholics are called cheonjugyo and Protestants often gidokgyo, which can make them sound like different religions. Both worship the same triune God. Korean Catholicism began when scholars read Christian books on their own and Yi Seung-hun was baptised in Beijing in 1784. Protestantism took root in the 1880s.

Jesus prayed that his followers might be one.

that all of them may be one, as You, Father, are in Me, and I am in You. May they also be in Us, so that the world may believe that You sent Me.

John 17:21

Without making light of the differences, hearing what another church believes in its own words is one way to answer that prayer.

You might ask yourself: Have I ever heard another church's teaching in its own words? What is my final authority, and why? What can we confess together despite our differences?

To read further, see What is justification? and Why do we need the church?.