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What is Catholicism?

Catholics believe in one God who exists as Father, Son and Holy Spirit, that Jesus Christ is fully God and fully man, that he died for our sins and rose bodily from the dead. Catholicism also places authoritative weight to Traditions, Mary (& the Saints), sacraments and the Catholic Church (priesthood and the role of the Pope).

For the Christian talking to a Catholic, the deeper questions to generally ask are, "Where has Christ placed final authority for His Church - in Scripture alone, or with Sacred Tradition and the authority of the Catholic church? And are we justified before God through faith in Christ alone, or through a sacramental life in which faith is expressed through works of love?"

Key facts​

Catholicism traces its origin to just after the apostles died. Catholics understand the Roman Catholic Church to be the continuation of the church established by Christ and the community entrusted with the apostles' teaching.

The Church's doctrines and institutional structures developed over many centuries. The papacy, sacramental theology, doctrines concerning Mary and the saints, purgatory, and other distinctive Catholic teachings developed progressively through the history of the Church.

Catholics regard the Pope as the successor of the apostle Peter and the bishops as successors of the apostles. The Church therefore claims not merely to preserve Christian teaching but to possess Christ-given authority to teach and interpret it.

It is therefore historically reasonable to distinguish the Christianity of the New Testament and earliest Church from the fully developed theological and institutional system of later Roman Catholicism.

Overview​

History​

Catholicism is the largest historic Christian tradition and is centred on the Roman Catholic Church, headed by the Bishop of Rome (the Pope). The shift from the New Testament model to the Catholic system happened in three major waves.

First, during the Post-Apostolic Era (100–300 AD), the early church faced severe persecution and internal divisions. To survive, local communities abandoned the New Testament model of shared local elders. Instead, they concentrated power under a single ruling bishop per city. Leaders also began viewing themselves as Old Testament-style priests who mediated between God and man.

Second, the Imperial Era (300–600 AD) began when Emperor Constantine legalised Christianity, eventually making it Rome's official state religion. As millions of pagans flooded the church, they brought their old customs with them. Statues entered churches, and praying to local Roman gods was replaced by praying to Christian saints and martyrs. It was also during this time that devotion to Mary grew from basic respect into formal doctrine.

Finally, the Middle Ages (600–1500 AD) saw the Roman church codify its most stark deviations from Scripture into law. The church introduced Purgatory and sold indulgences, conflicting with the biblical view of salvation as a free gift. In 1123 AD, they banned priests from marrying - even though the Apostle Peter was married. By 1215 AD, the church mandated private confession to a priest and declared that the bread and wine become the actual body and blood of Christ. This evolution was finalized at the Council of Trent (1545 AD), which declared Church Tradition completely equal to the Bible.

The Reformation in 1517 AD was a return to Scripture as the primary authority over tradition. The people of this movement later became called the Protestants, as it broke away from the church to Scripture alone.

Beliefs​

Catholicism shares many foundational Christian beliefs, but it also has a distinctive system of Church authority, sacraments, Mary, the saints, and the afterlife.

The Church and its authority: Catholics believe that Jesus established the Catholic Church and that the Church is guided by the Holy Spirit. The Pope, as Bishop of Rome, is regarded as the successor of the Apostle Peter and the Church's highest earthly authority. Catholics look to both Sacred Scripture and Sacred Tradition as authoritative sources of Christian teaching.

Mary: Catholics honour Mary as the mother of Jesus and give her a unique place among God's people. They believe that Mary was conceived without original sin (the Immaculate Conception), remained a virgin, was the Mother of God, and at the end of her earthly life was taken bodily into heaven (the Assumption). Catholics venerate Mary, bowing to and praying to her, asking her to intercede for them.

The saints: Catholics believe that Christians who have died in God's grace can be with God in heaven and are called saints. Catholics honour these saints and may bow to and ask them to intercede for them, rather than regarding such prayer as worship. Special honour is given to Mary.

The sacraments: Catholics recognise seven sacraments: Infant baptism, confirmation, the Eucharist, penance (confession to a priest), anointing of the sick, Holy Orders, and matrimony. They believe these are effective means through which God gives grace.

Confession and forgiveness: Catholics believe that sins committed after baptism must be confessed to a priest, who acts in the ministry of Christ and the Church. Through the sacrament of Penance, the repentant sinner receives God's forgiveness and reconciliation with the Church.

The Eucharist: Catholics believe that in the Mass, the bread and wine become the true Body and Blood of Jesus Christ while retaining the appearances of bread and wine. This teaching is known as transubstantiation. The Eucharist is therefore central to Catholic worship.

Purgatory: Catholics believe that some people who die might not be fully purified from the effects of sin. They therefore undergo purification in Purgatory before entering the fullness of heaven. Purgatory is not considered a second chance at salvation, but a purification of those who will ultimately be with God.

Indulgences: Indulgences may be partial or complete, and can be applied to oneself or, to a deceased person. They are obtained through prescribed acts of faith and charity, such as prayer, acts of mercy, or other works designated by the Church. These may be obtained by family members on behalf of those believed to be in purgatory, in order to reduce their time of purification.

Salvation and grace: Catholicism teaches salvation through Christ and God's grace, but places that salvation within a system of Church authority, sacraments, confession, devotion to Mary and the saints, and purgatory. Protestants say that this compromises the biblical doctrine of justification by faith i.e., that a sinner is declared righteous before God solely because of Christ's righteousness received through faith, rather than because of any righteousness produced in the believer. Works are important, but they don't buy salvation.

What attracts people to Catholicism?​

People may be drawn to Catholicism because of its long history, reverent worship, strong sense of tradition, and emphasis on the authority of the Catholic church. The Mass, sacraments, liturgy and symbolism can provide a deep sense of continuity with the historic Christian faith.

Others are attracted by Catholic teaching on the family, morality, charity, forgiveness, and the importance of community. The Catholic church also offers a structured spiritual life through prayer, confession, the Eucharist, fasting, and the church calendar.

Catholicism also gives people a framework for questions about sin, suffering, death, and eternity. Its teaching about Purgatory can offer reassurance that God continues to purify His people after death (i.e. they have time, although not Biblical), while devotion to Mary and the saints can provide a sense of spiritual companionship and intercession. For many Catholics, the Catholic church's sacraments and the assurance of receiving God's grace through them are an important part of their life.

Sharing the Gospel​

Remember: this is a guide, not a script. Ask the Holy Spirit to guide the conversation.

Have a conversation, not a presentation. A Catholic generally already believes that Jesus is the Son of God, that He died for our sins, that He rose again, and that He established His Church. So the conversation doesn't need to begin by proving those things. Instead, begin with something personal:

How do you know that you are right with God?​

Ask:

"How do you know that you are right with God?"

Let them answer. Then ask:

"If someone wanted to be right with God, what would they actually need to do?"

This naturally brings us to the most important question.

What must I do to be saved?​

Ask:

"What does the Bible say a person must do to be saved?"

Now read what Scripture actually says. The goal isn't to attack Catholic people or assume that Catholics don't love Jesus. The goal is to put the claims of the Catholic system alongside Scripture and ask, "What does the Bible actually teach?" Ultimately, this is what we will be judged by one day.

Read Acts 16:30–31 "What must I do to be saved?" The answer is: "Believe in the Lord Jesus and you will be saved." Ask:

"What did Paul tell him to do?"

"Do you know the story of Nicodemus in the Gospel of John?"

Nicodemus was a religious leader and devout on keeping the law. When he had questions, Jesus said, "Unless one is born again, he cannot see the kingdom of God."

Then read John 3:1–8. Ask:

"What does Jesus say is necessary to enter the kingdom of God?"

Not simply:

"Are you Catholic?"

Not:

"Have you been baptized?"

Not:

"Do you attend Mass?"

Jesus says:

"You must be born again."

What does it mean to be born again?​

Ask:

"What do you think Jesus means when He says you must be born again?"

Then read John 3:5–8 again. Jesus connects being born again with being born of the Spirit. Ask:

"Has this happened to you?"

"Have you personally been born of the Spirit?"

This is where the conversation becomes personal.

Now we can bring in Mary as well.

What about Mary?​

Mary gives us a beautiful example of someone who needed God and submitted herself to Him. Read Luke 1:26–38. Mary responds to God's announcement with humility and faith. Then read Luke 1:46–47 "My soul magnifies the Lord, and my spirit rejoices in God my Savior."

Ask:

"Who does Mary call her Savior?"

Mary points us to God as her Savior. Then read Acts 1:12–14 Mary is with the disciples after Jesus' ascension, waiting and praying for the promised Holy Spirit. Ask:

"What is Mary doing here?"

"Is Mary herself the source of salvation, or is she also looking to God?"

Then make it personal again:

"If Mary needed a Savior, do you and I need one too?"

"If Jesus says we must be born again, have you been born again?"

"Have you received the Holy Spirit?"

Notice we are not attacking Mary. We are letting Mary point the person to Jesus, just as she does in Scripture. She too like everyone of us needed Jesus, as her Lord and Saviour.

When the conversation becomes personal​

Some questions are theological. Others are deeply personal. Now ask:

"Have you been born again?"

"Have you received the Holy Spirit?"

"Are you trusting in Jesus Christ for your salvation?"

"Do you know that your sins are forgiven?"

"If you stood before God today, what would you be trusting in?"

Give them time to answer. Then go back to Scripture.

How are we made right with God?​

Catholics believe justification begins by God's grace, but is understood as an ongoing transformation in which the believer cooperates with grace through faith, the sacraments, obedience and love, and must persevere in grace. The Bible says that we are justified once for all by God's grace through faith in Christ, on the basis of Christ's finished work - not because of anything we contribute.

Read Romans 3:21–28. Ask:

"According to Paul, how is a person justified?"

"What does Paul say about works?"

Then read Ephesians 2:8–10

Notice the order - We are saved by grace through faith. It is God's gift. It is not from ourselves. It is not the result of works. Then we are created in Christ for good works.

Ask:

"Are good works the cause of salvation, or the result of salvation?"

This is an important distinction.

Please don't tell a Catholic "You think you can earn salvation." Catholic theology explicitly rejects that. Instead ask:

"If salvation is God's gift, received through faith, what am I trusting in when I stand before God?"

What did Jesus accomplish?​

Now turn from how we are saved to what Jesus did to save us. Read John 19:28–30 Jesus says, "It is finished." Ask:

"What did Jesus say was finished?"

Then read Hebrews 10:10–14

Jesus offered Himself once for all.

Ask:

"How many times did Jesus offer Himself?" "What does 'once for all' tell us about His sacrifice?"

Then read Romans 5:1, "Therefore, since we have been justified through faith, we have peace with God through our Lord Jesus Christ." Now ask:

"Where does our peace with God come from?"

The conversation now points back to the Gospel again - we were sinners. Christ died for sinners. Christ rose again. Salvation is God's gift. We receive Christ through faith. We are justified through faith. We are called to live transformed lives because we have been saved.

Examining the Catholic practices​

Only after the Gospel has been clearly established should you begin asking what and why Catholic practices add to that picture. Please don't say things like "Catholicism is wrong because…" as that gets people defensive rather than examining with the Scripture says for themselves. Let the Word speak to them, let Holy Spirit bring conviction - that's not our job. Frame questions like:

"Does this teaching fit with the Gospel we have just seen in Scripture?"

"I've never understood why this is done, can you explain it please?"

So for example start with:

"If that is what the Bible says about salvation, how do we understand some of the things the Catholic Church teaches and practices?"

Now you can explore several things and highlight what Scripture actually says.

The Mass - Is Christ's sacrifice sufficient?​

Read Hebrews 10:11–14. Ask:

"If Jesus offered one sacrifice for sins for all time, what is the continuing sacrificial role of the Mass?"

Confession - Who forgives sins?​

Read 1 John 1:9, "If we confess our sins, He is faithful and just to forgive us our sins." Ask:

"Who does John tell us to confess our sins to?"

Then read James 5:16, "Confess your sins to one another and pray for one another."

Ask:

"Does James say 'confess your sins to a priest,' or does he say 'one another'?"

"Does the priest ever confess his sins to you?

"Why do you pray (penance) for yourself, if it says pray for the other?"

Then discuss John 20:21–23 honestly, since this is an important Catholic text concerning the apostles' authority regarding forgiveness.

Christians should absolutely confess sin. If they have wronged someone they should make that right before going to God. That's the context of this verse and what Jesus says in Matthew 5:24, but we cannot confess sins to a priest in order to receive God's forgiveness

Peter - Who is the foundation?​

Read Matthew 16:13–20. Ask:

"What does Jesus mean by 'this rock'?"

Then read the next two verses Matthew 16:21–23, Peter is immediately rebuked by Jesus: "Get behind Me, Satan!"

The point isn't that Peter had no authority. It is that Peter was still capable of seriously misunderstanding Jesus. It is that Peter wasn't perfect or could substitute Jesus' place.

Then read, Ephesians 2:19–22 and 1 Corinthians 3:11. Ask:

"Who does Scripture identify as the cornerstone?"

"Who is the foundation ultimately built upon?"

The answer keeps taking us back to Christ.

Could the church be founded on Peter?

If we're saying Peter is the rock, then we should also take the next verse that says he is Satan, and that would mean that the same holds true for the Catholic church… No, the rock is the revelation Peter had - Jesus is the Messiah, the Son of God.

Jesus is the only person who could be the cornerstone. Peter was one of his closest followers and the one Jesus entrusted to teach the people to repent, be saved and follow Christ.

Mary - Where does she point us?​

Now that the person has already considered Mary's own need for God, return to John 2:1–11. Mary's instruction is simple: "Do whatever He tells you." Ask:

"Who does Mary direct people toward?"

Jesus. Then read 1 Timothy 2:5 "For there is one God and one mediator between God and men, the man Christ Jesus." Ask:

"If Jesus is the one mediator between God and humanity, where does Scripture instruct us to pray to Mary?"

Again, the purpose isn't to diminish Mary. It is to follow where Mary herself points. After exploring these passages, return to the beginning. Ask:

"You told me earlier how you believe you are right with God. After looking at these passages, has your answer changed?"

And finally:

"Are you trusting in Christ and His finished work, or are you trusting in Christ plus something else?"

The goal is not simply to convince someone that Catholicism has doctrinal problems. The goal is to bring them to Jesus Christ. The ultimate question is not "Are you Catholic or Protestant?" It is:

  • "Have you been born again?"
  • "Do you have the Holy Spirit?"
  • "Are you trusting Christ?"
  • "Do you know that you have eternal life?"
  • "Is Christ's finished work sufficient for you?"

Questions to Ask​

About salvation​

  • How do you know that you are right with God?
  • What must a person do to be saved?
  • Have you been born again?
  • Have you received the Holy Spirit?
  • What are you trusting in for your salvation?
  • Can you know that your sins are forgiven?
  • Is Christ's finished work sufficient to save you?

About justification​

  • On what basis does God declare a sinner righteous?
  • Is justification a once-for-all declaration, or an ongoing process?
  • If salvation is by grace, what role do our works play?
  • If Christ has paid for our sins, what remains for us to contribute?
  • Can a justified person have assurance of salvation?

About Scripture and authority​

  • How do you know that the Church is teaching the truth?
  • If the Church interprets Scripture, how do we test the Church's interpretation?
  • Where does Scripture establish the authority of the Magisterium?
  • Where does Scripture establish the Pope as the universal successor of Peter?
  • If a doctrine cannot clearly be found in Scripture, what establishes it as Christian truth?
  • Is the Church under Scripture, or does the Church possess authority alongside it?

About the Mass​

  • What do you believe happens during the Mass?
  • Is the Mass a sacrifice?
  • If Christ offered Himself once for all, why is there a continuing sacrificial offering?
  • What does Hebrews mean when it says Christ offered one sacrifice for sins for all time?
  • If Jesus said "It is finished," what was finished?

About confession​

  • Who does the Bible tell us to confess our sins to?
  • Why must I confess my sins to a priest?
  • Where does Scripture say that priestly confession is necessary for forgiveness?
  • What does James mean when he says to "confess your sins to one another"?
  • If God forgives sins, why do I need a priest to receive that forgiveness?

About Peter and the Pope​

  • What authority did Jesus actually give Peter?
  • Is Peter the only foundation of the Church?
  • Who does Paul call the cornerstone?
  • Where does Scripture establish Peter's successors as universal bishops?
  • Where does Scripture teach that a Pope cannot err when speaking infallibly?
  • If Peter himself could be seriously wrong, what establishes infallibility for his successors?

About Mary​

  • Who does Mary say is her Savior?
  • Does Mary herself point people toward Jesus?
  • Where does Scripture instruct Christians to pray to Mary?
  • Where does Scripture instruct us to seek Mary's intercession?
  • If Jesus is the one mediator between God and humanity, why do we need another heavenly mediator?
  • What does Scripture actually teach about the Immaculate Conception, Assumption and perpetual virginity?

About the saints​

  • Where does Scripture tell Christians to pray to departed saints?
  • Why should I ask a saint to pray for me when I can pray directly to God?
  • If Jesus is our High Priest, why do I need another heavenly intercessor?
  • Does Hebrews tell us to fix our eyes on the saints, or on Jesus?

About purgatory​

  • Where does Scripture clearly teach purgatory?
  • If Christ completely paid for sin, what remains for the believer to pay after death?
  • What does Hebrews mean when it says Christ perfected His people by one offering?
  • When Jesus forgives someone, is that forgiveness complete?
The most important question

If Jesus has completely paid for your sins, what are you trusting in besides Jesus?

Common questions and objections​

But Catholics believe in salvation by grace​

They do. Catholic theology explicitly teaches that salvation begins with God's grace and cannot be earned independently of it. The question is therefore more precise: "If justification is God's gracious gift, what role do sacraments, obedience and works play in the basis of our justification?"

Faith without works is dead​

Absolutely. The question is whether works are the basis of our justification before God, or the fruit and evidence of genuine faith. Compare Romans 3:28 with James 2:14–26.

The Bible says Peter is the rock​

It does say, "You are Peter, and on this rock I will build My church" (Mat 16:18). Don't avoid the passage. Ask what Jesus means by "this rock," then ask where Scripture establishes Peter as a continuing universal office whose authority passes to the Pope. See the section above that explains this in depth.

Jesus gave the apostles authority to forgive sins​

The strongest passage is John 20:21–23, and it deserves to be taken seriously. Ask what authority Jesus gave the apostles, then compare it with the New Testament's repeated teaching that forgiveness comes from God through Christ. See the section above that explains this in depth.

We don't worship Mary​

Catholicism distinguishes worship owed to God from honour given to Mary and the saints, so don't accuse Catholics of believing Mary is a goddess. Instead ask, "Where does Scripture instruct Christians to pray to Mary or seek her intercession?" See the section above that explains this in depth.

Mary was sinless​

Catholicism teaches the Immaculate Conception, meaning Mary was preserved from original sin from the moment of her conception. Ask "where does Scripture teach this?" Mary wouldn't need a saviour if she was sinless, yet even she says she does. Then read Mary's own words, "My spirit rejoices in God my Savior" (Luke 1:46–47).

We don't sacrifice Jesus again at Mass​

Catholic theology does not teach that Jesus is repeatedly killed. Rather, the Mass is understood as making Christ's one sacrifice present sacramentally. Ask, "why does Hebrews place such emphasis on Christ's one, once-for-all offering?"

The Church gave us the Bible​

The Church played an important historical role in preserving and recognising the biblical canon. But ask the deeper question, "Does the Church's role in recognising Scripture mean that the Church has authority to create doctrines that cannot be established from Scripture?" The Bereans themselves examined Paul's teaching against Scripture (Act 17:11).

You need a priest because Jesus gave priests authority​

Ask where the New Testament establishes a separate Christian priesthood that functions as a necessary mediator between ordinary believers and God. Then read 1 Peter 2:9, where Christians collectively are described as a royal priesthood.

Confession to a priest is biblical​

James certainly commands Christians to confess sins to one another (Jam 5:16), especially when they've wronged them. That's the context of this verse and what Jesus says in Matthew 5:24, but we cannot confess sins to a priest in order to receive God's forgiveness

Ask "Where does James say that Christians must confess their sins sacramentally to a priest in order to receive God's forgiveness?" Then compare it with 1 John 1:9: "If we confess our sins, He is faithful and just to forgive us our sins." See the section above that explains this in depth.

You need the sacraments to receive God's grace​

Catholic theology understands the sacraments as ordinary means through which God's grace is given. The question to explore is: Which of these things does Scripture actually make necessary for justification, and what does Scripture say about being justified through faith? Read Romans 3:21–28 and Ephesians 2:8–10

Catholics have always believed this​

Historical continuity is worth discussing, but it doesn't settle whether a doctrine is true. Ask: "If something has been believed for a long time, does that prove it is biblical?" Then return to Scripture: What did Jesus and the apostles actually teach?

Helpful Bible passages​

Salvation and justification​

  • John 3:1–8 Jesus says that a person must be born again and born of the Spirit.
  • John 3:14–18 Whoever believes in the Son has eternal life.
  • John 5:24 Whoever hears and believes has eternal life and has passed from death to life.
  • Acts 16:30–31 "What must I do to be saved?" Believe in the Lord Jesus.
  • Romans 3:21–28 Justification through faith apart from works of the law.
  • Romans 4:1–8 Righteousness credited by faith rather than earned as wages.
  • Romans 5:1 Having been justified through faith, we have peace with God.
  • Romans 8:1 There is now no condemnation for those in Christ Jesus.
  • Ephesians 2:1–10 Saved by grace through faith, resulting in good works.
  • Titus 3:4–7 Saved according to God's mercy, not righteous deeds we have done.
  • 1 John 5:11–13 Written so believers may know that they have eternal life.

Christ's finished work​

Church and authority​

  • Matthew 16:13–23 Peter, the rock, and Peter's immediate rebuke by Jesus.
  • Matthew 18:15–20 Authority and discipline given to the wider body of disciples.
  • Acts 17:10–12 The Bereans examine Paul's teaching against Scripture.
  • Galatians 1:6–9 Even an angelic message must not replace the true Gospel.
  • Ephesians 2:19–22 The household of God built on the foundation of apostles and prophets, with Christ as cornerstone.
  • 1 Corinthians 3:11 "No one can lay a foundation other than the one already laid, which is Jesus Christ."

Mary​

Confession and forgiveness​

A challenge for Christians​

Catholicism should challenge us too.

We can argue that salvation is by grace while secretly trusting in our own performance.

We can criticise sacramentalism while treating church attendance as a substitute for actually knowing Christ.

We can argue about Mary while neglecting the example of Mary's humility and obedience.

We can talk about Scripture being our authority while rarely opening it.

Am I trusting completely in Jesus Christ and His finished work? Am I walking by the Spirit? Do I love God and love people?

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