What Is Christianity? Beliefs, History, and Practices
Christianity stands as the world’s largest religion, with over 2.4 billion adherents spanning every continent and culture. From humble beginnings in first-century Palestine to its current global presence, Christianity has profoundly shaped art, philosophy, law, ethics, and countless aspects of human civilization. Yet for all its familiarity, many people have only a surface understanding of what Christians actually believe and practice.
Overview of Christianity
Christianity emerged from Judaism in the first century CE, founded on the life, teachings, death, and resurrection of Jesus of Nazareth, whom Christians believe to be the Son of God and the promised Messiah. The name “Christian” itself means “follower of Christ,” with “Christ” being the Greek translation of the Hebrew “Messiah,” meaning “anointed one.”
What began as a small Jewish sect in Roman-occupied Palestine grew rapidly throughout the Mediterranean world. Early Christians faced persecution under Roman authorities, yet the faith spread through the testimonies of apostles, the appeal of its message about divine love and redemption, and the strength of its communities. Emperor Constantine’s Edict of Milan legalized Christianity, and by the end of the fourth century, it had become the Roman Empire’s official religion.
Christianity is fundamentally a monotheistic faith centered on a personal relationship with God through Jesus Christ. Unlike religions focused primarily on following laws or achieving enlightenment through personal effort, Christianity emphasizes salvation as a gift received through faith in Christ’s redemptive work. This grace-centered theology distinguishes it from many other religious systems and shapes its distinctive character.
The religion’s universal appeal lies partly in its message that God loves all humanity regardless of social status, ethnicity, or past failures. Early Christianity attracted slaves, women, and marginalized people by proclaiming their equal worth before God—a radical notion in the ancient world’s hierarchical societies.
Core Beliefs of Christianity
While Christian denominations differ on various doctrinal points, several core beliefs unite nearly all Christians across traditions.
– The Trinity stands as Christianity’s most distinctive doctrine. Christians believe in one God who exists eternally in three persons: Father, Son, and Holy Spirit. These are not three separate gods but one divine being existing in three distinct persons, each fully God yet together comprising one Godhead. This mysterious doctrine, developed in the early centuries of Christianity, attempts to honor both biblical monotheism and the New Testament’s presentation of Jesus and the Holy Spirit as divine.
– The Incarnation proclaims that God became human in Jesus Christ. Christians believe Jesus was both fully divine and fully human not half-and-half, but completely both. This belief means God didn’t merely send a messenger or appear in human form temporarily; God actually entered human existence, experiencing life, suffering, and death firsthand. The incarnation demonstrates God’s profound love and solidarity with humanity.
– Sin and Salvation form Christianity’s central narrative. Christians believe humanity has fallen from its intended relationship with God through sin a condition of separation from God affecting all people. This isn’t merely about individual wrongdoings but a fundamental brokenness in human nature and our relationship with our Creator. Salvation restoration to right relationship with God cannot be achieved through human effort alone. Instead, Christians believe Jesus Christ’s death on the cross paid the penalty for human sin, and his resurrection conquered death. Salvation comes through faith in Christ’s redemptive work, not through earning God’s favor.
Grace is the unmerited favor and love God extends to humanity. Christianity teaches that people cannot save themselves through good deeds, religious observance, or moral perfection. Instead, salvation is a gift freely given to those who trust in Christ. This doctrine of grace has profound implications for Christian ethics and self-understanding, emphasizing humility and gratitude rather than self-righteousness.
Resurrection and Eternal Life constitute Christianity’s ultimate hope. Christians believe Jesus physically rose from the dead three days after his crucifixion an event they consider historical fact, not metaphor. This resurrection validates Jesus’s divine identity and promises that believers will likewise be resurrected to eternal life. Christianity thus offers hope beyond death, proclaiming that physical existence matters and will be redeemed, not merely escaped.
Love as the Greatest Commandment summarizes Christian ethics. Jesus taught that the entire law could be summed up in two commands: love God with all your heart, soul, and mind, and love your neighbor as yourself. This love ethic extends even to enemies, calling Christians to forgiveness, compassion, and self-sacrifice modeled on Christ’s own example.
The Bible and Christian Teachings
The Bible serves as Christianity’s sacred scripture and primary authority for faith and practice. It comprises two main sections: the Old Testament, shared with Judaism and containing texts written before Christ, and the New Testament, containing writings about Jesus and the early church.
The Old Testament includes 39 books (in Protestant traditions; Catholic and Orthodox traditions include additional texts) spanning history, law, poetry, wisdom literature, and prophecy. Christians read these ancient Hebrew scriptures through the lens of Christ, seeing them as preparation for and prophecy about Jesus’s coming. The creation accounts, the covenant with Abraham, the exodus from Egypt, the giving of the law through Moses, and the prophetic promises of a coming Messiah all find their fulfillment, Christians believe, in Jesus Christ.
The New Testament consists of 27 books written in the first century CE. The four Gospels—Matthew, Mark, Luke, and John—provide accounts of Jesus’s life, teachings, death, and resurrection, each offering unique perspectives and emphases. The Acts of the Apostles chronicles the early church’s formation and spread. The Epistles, letters written by early Christian leaders like Paul, Peter, and John, address theological questions and practical issues facing early Christian communities. The Book of Revelation presents apocalyptic visions of the end times and Christ’s ultimate triumph.
Christians approach the Bible with various interpretive methods. Some read it as literally true in all details; others recognize different genres within scripture—poetry, parable, history, apocalyptic literature—each requiring appropriate interpretive approaches. Most Christians agree the Bible is divinely inspired and authoritative for understanding God’s character and will, even when they disagree about specific interpretations.
Central teachings drawn from scripture include the Sermon on the Mount, where Jesus presents radical ethics of peacemaking, generosity, and integrity. The parables—story-based teachings using everyday situations to reveal spiritual truths—communicate profound insights about God’s kingdom, grace, and human nature. Jesus’s teachings emphasize inner transformation over external conformity, mercy over judgment, and the reversal of worldly values where the last become first and the humble are exalted.
Major Christian Practices
Christian faith expresses itself through distinctive practices that nurture spiritual life and community.
- Worship takes various forms but typically includes prayer, singing, scripture reading, and preaching. Sunday became the traditional day of worship, commemorating Jesus’s resurrection. Worship styles range from liturgical services following ancient patterns with formal prayers and ritual to contemporary gatherings with modern music and casual atmospheres. Despite stylistic differences, Christian worship centers on praising God, hearing scripture, and responding in faith.
- Sacraments (or ordinances, in some traditions) are sacred rituals instituted by Christ. Nearly all Christians practice two: baptism and communion (also called the Eucharist or Lord’s Supper). Baptism marks entry into Christian faith, symbolizing death to old life and resurrection to new life in Christ. Different traditions baptize infants or only adults who profess faith, and use immersion or sprinkling with water. Communion commemorates Jesus’s last supper with his disciples before his crucifixion, where bread and wine represent Christ’s body and blood. Some traditions believe Christ is literally present in these elements; others view the ritual as symbolic remembrance.
- Prayer forms the backbone of Christian spiritual life. Christians pray individually and corporately, speaking to God about anything from daily concerns to global crises. Prayer practices include adoration, confession, thanksgiving, and supplication. Some Christians follow structured prayer liturgies like the Lord’s Prayer Jesus taught; others prefer spontaneous conversation with God. Contemplative traditions emphasize silent prayer and meditation, listening for God’s presence rather than speaking.
- Reading Scripture grounds Christians in their faith tradition. Many follow daily Bible reading plans, study scripture in groups, or memorize passages. The practice of lectio divina—a slow, meditative reading of scripture—has been renewed in recent decades, offering an alternative to purely analytical study.
- Service and Mission flow from Christian faith. Jesus emphasized serving others, particularly the poor, sick, and marginalized. Christians engage in charitable work, social justice advocacy, and evangelism—sharing their faith with others. Mission work, both local and international, aims to meet physical needs while introducing people to Christian faith.
- Celebration of the Church Calendar structures time around events in Jesus’s life. Major celebrations include Christmas (Jesus’s birth), Easter (his resurrection), and Pentecost (the Holy Spirit’s coming to the early church). Advent prepares for Christmas; Lent prepares for Easter through fasting and reflection. These seasons help Christians regularly rehearse their faith’s central narratives.
Christian Denominations
Christianity encompasses remarkable diversity, with thousands of denominations reflecting theological differences, cultural contexts, and historical developments.
Catholicism, with over 1.3 billion adherents, represents Christianity’s largest branch. Led by the Pope in Rome, Catholicism emphasizes apostolic succession—the belief that church authority traces directly to the apostles through the papacy. Catholics recognize seven sacraments, venerate Mary and the saints, and consider both scripture and church tradition authoritative. Catholic worship centers on the Mass, where priests consecrate bread and wine that Catholics believe becomes Christ’s actual body and blood.
1. Eastern Orthodox Christianity separated from Catholicism in 1054 CE over theological and jurisdictional disputes. Orthodox churches—Greek, Russian, Serbian, and others—maintain ancient liturgical traditions, emphasize mysticism and theosis (becoming one with God), and reject papal authority while honoring patriarchs of various regional churches. Orthodox worship features elaborate rituals, icons, and chanting that engage all senses.
2. Protestantism emerged from the 16th-century Reformation when reformers like Martin Luther challenged Catholic doctrines and practices. Protestants emphasize scripture alone as authority, salvation by faith alone, and the priesthood of all believers. This branch encompasses enormous diversity, from liturgical Lutherans and Anglicans to evangelical Baptists and Pentecostals. Key Protestant principles include direct access to God without priestly mediation and the right of individuals to interpret scripture.
3. Anglicanism occupies a middle ground between Catholicism and Protestantism, retaining episcopal structure and liturgical worship while embracing Protestant theology. The global Anglican Communion includes diverse expressions from traditional Church of England congregations to charismatic African churches.
4. Evangelicalism, cutting across denominational lines, emphasizes personal conversion, biblical authority, evangelism, and Christ’s atoning death. Evangelical churches range from Baptist and Methodist to non-denominational megachurches. This movement has become particularly influential in American Christianity.
5. Pentecostalism and Charismatic Christianity stress the Holy Spirit’s active presence, spiritual gifts like speaking in tongues and healing, and experiential worship. Pentecostalism has exploded globally, becoming Christianity’s fastest-growing expression, particularly in Latin America, Africa, and Asia.
6. Progressive Christianity represents a more recent movement reinterpreting traditional doctrines through lenses of social justice, inclusivity, and critical biblical scholarship. Progressive Christians often emphasize Jesus’s teachings on peace and justice over supernatural doctrines.
These divisions sometimes create tension, yet many Christians today emphasize unity in essential beliefs while accepting diversity in secondary matters. Ecumenical movements seek common ground and cooperation across denominational boundaries.
Global Spread of Christianity
Christianity’s journey from Palestinian sect to global religion represents one of history’s most remarkable transformations.
Early expansion occurred throughout the Roman Empire despite periodic persecution. Missionaries like Paul established churches across Asia Minor and Europe. Christianity’s message of universal salvation, its care for the poor and sick, and the courage of martyrs who died for their faith all contributed to its growth.
After becoming Rome’s official religion, Christianity spread with empire and political power. Missionaries evangelized Germanic tribes in northern Europe. The conversion of rulers often meant entire populations adopting Christianity, whether willingly or under coercion. This mixing of Christianity with political power created complex legacies of both civilizational advancement and oppression.
The East-West split in 1054 created distinct spheres of influence. Western Christianity, centered in Rome, dominated Western Europe. Eastern Orthodoxy prevailed in Eastern Europe, Russia, and parts of the Middle East. Each developed unique cultural expressions of Christian faith.
European colonization from the 15th century onward spread Christianity globally, often intertwining evangelism with conquest and exploitation. Missionaries accompanied colonizers to the Americas, Africa, and Asia. This legacy is deeply ambiguous—bringing literacy, healthcare, and education while also participating in cultural destruction and supporting oppressive systems.
Indigenous converts and missionaries gradually made Christianity authentically local rather than merely European. African Christianity developed vibrant expressions blending biblical faith with African culture. Latin American Christianity, initially imposed by Spanish and Portuguese conquerors, became deeply rooted through local devotion and liberation theology. Asian Christianity has adapted to diverse cultural contexts while maintaining core beliefs.
Today’s Christianity has shifted dramatically southward and eastward. While declining in Europe and parts of North America, Christianity grows rapidly in sub-Saharan Africa, Latin America, and parts of Asia. Nigeria, Brazil, and China now house some of the world’s largest Christian populations. This shift has created more diverse global Christianity where African, Asian, and Latin American voices increasingly shape the faith’s future.
Christianity Today
Contemporary Christianity navigates tension between tradition and change in rapidly evolving contexts.
Demographic shifts are reshaping global Christianity. The typical Christian today is more likely to be a woman from Nigeria or Brazil than a man from Europe or North America. This southern shift brings different theological emphases, worship styles, and social concerns. African and Asian Christianity tends toward more conservative theology and charismatic worship, while Western Christianity increasingly divides between progressive and conservative camps.
Secularization challenges Christianity in developed Western nations. Church attendance has declined significantly in Western Europe, Canada, and increasingly the United States. Many Western young people identify as spiritual but not religious or abandon faith altogether. Churches struggle to remain relevant in cultures valuing individualism, skepticism toward authority, and scientific worldviews.
Yet Christianity simultaneously experiences renewal and growth in other contexts. Chinese Christianity, despite government restrictions, may number over 100 million believers. African Christianity’s explosive growth combines evangelistic zeal with cultural adaptation. Even in the West, some communities experience vitality through innovative approaches or countercultural commitment.
Social and ethical debates create division and soul-searching. Christians disagree sharply on issues like same-sex relationships, gender identity, women’s roles in church leadership, abortion, economic justice, immigration, and environmental stewardship. These debates reflect broader tensions about biblical authority, cultural engagement, and faithfulness to tradition versus adaptation to contemporary understanding.
Interfaith relations challenge Christianity to engage respectfully with religious pluralism. Some Christians maintain exclusive salvation claims while engaging in dialogue; others adopt more inclusive theologies recognizing truth in other traditions. Encounters with Islam, Hinduism, Buddhism, and other faiths have enriched some Christians’ understanding while prompting others to sharpen distinctives.
Technology transforms Christian practice. Online services expanded dramatically during COVID-19, raising questions about virtual versus physical community. Bible apps, Christian podcasts, and social media reshape how people encounter faith. Megachurches use production values rivaling concerts; small groups connect via video calls. These changes offer new opportunities and raise concerns about authentic community and depth.
Social justice movements animate many Christians. From civil rights to poverty relief, environmental activism to anti-trafficking work, Christians across the spectrum engage social issues motivated by faith. Liberation theology emphasizes God’s preferential option for the poor. The Catholic Church champions a consistent ethic of life. Evangelical leaders increasingly address systemic injustice. Yet Christians also disagree intensely about proper political engagement and social priorities.
Christianity today is not monolithic but a diverse global movement adapting to vastly different contexts while maintaining connection to ancient beliefs about Jesus Christ. It remains dynamic, contested, and significant—continuing to shape billions of lives and influencing global culture, politics, and ethics. Whether growing or declining in particular regions, Christianity’s two-thousand-year journey continues, driven by believers convinced that Jesus Christ remains humanity’s hope and God’s definitive self-revelation to the world.
Understanding Christianity requires appreciating both its unity and diversity—the core beliefs that bind Christians together and the many expressions those beliefs take across cultures, denominations, and historical periods. From grand cathedrals to house churches, from scholarly theology to simple faith, Christianity continues seeking to embody its founder’s vision of God’s kingdom breaking into human history with transforming love.