Is the Catholic Church part of Christianity or is it a separate religion?

TL;DR:

Roman Catholicism, as a religious system, diverges from biblical Christianity in significant ways, including its teachings on salvation, the veneration of Mary, and the role of priests. While many Catholics are sincere in their faith and may be born-again believers, the official doctrines of Catholicism contain unbiblical elements that differentiate it from the teachings of Scripture.

what does the bible say?

Biblical Christianity is not defined by membership in a particular church but by faith in Jesus Christ and adherence to essential biblical doctrines. These include belief in one God (Deuteronomy 6:4–5; Mark 12:29–30), the deity and humanity of Jesus Christ (John 1:1, 14; Colossians 2:9), His death and resurrection for our sins (1 Corinthians 15:3–4), and salvation by grace through faith alone (Ephesians 2:8–9). The Catholic Church is considered part of Christianity but differs significantly from biblical teachings in areas like salvation, the veneration of Mary, and the role of priests. While the Bible emphasizes salvation by grace through faith alone, Catholic doctrine incorporates works, sacraments, and intercession through Mary and priests, which deviate from Scripture. Key biblical passages, such as 1 Timothy 2:5, affirm Jesus as the sole mediator, and Ephesians 2:8–9 highlights salvation as a gift of grace, not earned by works. Despite these doctrinal differences, even Catholics who personally trust in Jesus for salvation and align with biblical Christianity will be saved. Christians are encouraged to lovingly share the gospel and point all believers to the sufficiency of Christ and the authority of Scripture.

from the old testament

Deuteronomy 6:4–5: "Hear, O Israel: The LORD our God, the LORD is one. You shall love the LORD your God with all your heart and with all your soul and with all your might." This foundational declaration of monotheism is central to biblical faith and contrasts with the veneration of Mary or saints as intermediaries.
Isaiah 64:6: "We have all become like one who is unclean, and all our righteous deeds are like a polluted garment." Relying on human works is futile. The Bible teaches that salvation is by grace alone.

from the new testament

Ephesians 2:8–9 affirms that salvation is entirely a work of God’s grace, rejecting the idea that sacraments or works contribute to being saved: "For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast."
The Bible clearly teaches that Jesus is the only mediator between humanity and God, negating the necessity of priests or Mary as intermediaries (1 Timothy 2:5).
Matthew 27:51: "And behold, the curtain of the temple was torn in two, from top to bottom. And the earth shook, and the rocks were split." The tearing of the temple veil symbolizes direct access to God through Christ, without human mediation.
John 14:6: "Jesus said to him [Thomas], 'I am the way, and the truth, and the life. No one comes to the Father except through me.'" Jesus alone provides the way to God, leaving no room for additional mediators or intercessors. This goes against what the Catholic Church teaches.

implications for today

Roman Catholicism diverges from biblical Christianity in key areas, particularly in its teachings on salvation, the veneration of Mary, and the role of priests. The Catholic Church teaches a works-based approach to salvation, requiring adherence to sacraments and good deeds for grace. This contrasts with Scripture, which teaches that salvation is by grace through faith alone (Ephesians 2:8–9; Titus 3:5–7).

The veneration of Mary as a co-mediator and the necessity of priests for confession and absolution also stand in opposition to the Bible’s teaching of Christ as the sole mediator (1 Timothy 2:5). These practices elevate human figures to roles that Scripture reserves for Jesus alone. However, many Catholics do not fully understand or follow official church teachings and may hold personal beliefs that align with biblical Christianity. A born-again Catholic who places their faith solely in Jesus Christ for salvation can indeed be a true Christian.

Biblical Christianity calls all believers to follow Jesus as Lord, rely on His grace for salvation, and reject teachings that contradict Scripture. Christians should lovingly share the gospel with Catholics and others, encouraging reliance on God’s Word as the ultimate authority and on Jesus as the only way to salvation.

understand

Salvation is by grace through faith alone, not through works or sacraments.
Jesus is the sole mediator, not Mary or priests.
Catholics who trust in Jesus alone for salvation can be true Christians.

reflect

How does salvation by grace through faith alone shape your understanding of your relationship with God?
How can you ensure that your faith remains focused on Jesus as the sole mediator between you and God?
How can you share the gospel with others in a way that respects their beliefs while pointing them to the sufficiency of Christ?

engage

How do we navigate the differences between Catholic teachings and biblical Christianity when discussing salvation with others?
What are the potential challenges of reconciling the Catholic veneration of Mary with the biblical teaching of Jesus as the sole mediator?
How can we engage in conversations with Catholics to encourage a deeper understanding of salvation by grace and the role of Jesus in our faith?