Understanding the Faith
What do Christians believe, how do they pray and worship, and how did the Church grow from twelve Apostles to 2.4 billion people?
Core beliefs in plain words
One God, three Persons
God is one, yet Father, Son and Holy Spirit — the Holy Trinity. Not three gods, but one God in a communion of love.
God made everything good
God created the universe and made humans in his own image (Genesis 1:27). Sin — turning away from God — broke that harmony.
Jesus saves
God the Son became man in Jesus. By his death and resurrection he forgives sin and gives new, eternal life.
The Holy Spirit
The Spirit lives in believers, guides the Church and gives gifts such as wisdom, courage and love.
The Church
The family of believers, the “Body of Christ”, founded on the Apostles.
Eternal life
Christians believe in the resurrection of the body, the final judgment, and heaven — life forever with God.
The Apostles' Creed
I believe in God, the Father almighty, Creator of heaven and earth, and in Jesus Christ, his only Son, our Lord, who was conceived by the Holy Spirit, born of the Virgin Mary, suffered under Pontius Pilate, was crucified, died and was buried; he descended into hell; on the third day he rose again from the dead; he ascended into heaven, and is seated at the right hand of God the Father almighty; from there he will come to judge the living and the dead. I believe in the Holy Spirit, the holy catholic Church, the communion of saints, the forgiveness of sins, the resurrection of the body, and life everlasting. Amen.
An ancient summary of faith, used by Catholics and most Protestants. The longer Nicene Creed (AD 325/381) is shared by Catholic, Orthodox and most Protestant churches.
The Ten Commandments (Exodus 20; Deuteronomy 5)
- I am the Lord your God; you shall have no other gods before me.
- You shall not take the name of the Lord your God in vain.
- Remember to keep holy the Lord's Day.
- Honour your father and your mother.
- You shall not kill.
- You shall not commit adultery.
- You shall not steal.
- You shall not bear false witness against your neighbour.
- You shall not covet your neighbour's wife.
- You shall not covet your neighbour's goods.
This is the traditional Catholic and Lutheran numbering. Orthodox and most Protestant churches separate “no graven images” as the second commandment and join the last two.
The seven Sacraments
Sacraments are holy signs, given by Christ, through which God gives his grace. Catholics and Orthodox recognise seven; most Protestants recognise two (Baptism and the Lord's Supper).
1. Baptism
With water, washes away sin and makes us children of God and members of the Church.
2. Confirmation
Strengthens with the gifts of the Holy Spirit (Chrismation in the East).
3. Eucharist
Holy Communion — the Body and Blood of Christ, received at Mass. The “source and summit” of Christian life.
4. Reconciliation
Confession: God forgives sins through the priest.
5. Anointing of the Sick
Strength, peace and sometimes healing for the seriously ill.
6. Holy Orders
Ordination of deacons, priests and bishops.
7. Matrimony
Marriage — a lifelong covenant of love between a man and a woman.
The Church year
| Season / feast | When | Meaning |
|---|---|---|
| Advent | 4 Sundays before Christmas | Preparing for Jesus' coming |
| Christmas | 25 December (7 January for many Orthodox) | Birth of Jesus |
| Epiphany | 6 January | Visit of the Wise Men — Jesus revealed to the nations |
| Lent | 40 days from Ash Wednesday | Prayer, fasting and giving to the poor |
| Holy Week & Easter | March/April (first Sunday after the first full moon of spring) | Death and resurrection of Jesus — the greatest feast |
| Ascension | 40 days after Easter | Jesus returns to the Father |
| Pentecost | 50 days after Easter | The Holy Spirit comes — the “birthday of the Church” |
| Assumption | 15 August | Mary taken into heaven |
| All Saints & All Souls | 1 & 2 November | Honouring all saints and praying for the dead |
The Lord's Prayer
Our Father, who art in heaven, hallowed be thy name; thy kingdom come, thy will be done on earth as it is in heaven. Give us this day our daily bread, and forgive us our trespasses, as we forgive those who trespass against us; and lead us not into temptation, but deliver us from evil. Amen.
Taught by Jesus himself (Matthew 6:9–13; Luke 11:2–4). Many Protestants add: “For thine is the kingdom, and the power, and the glory, for ever and ever.”
Glory Be
Glory be to the Father, and to the Son, and to the Holy Spirit, as it was in the beginning, is now, and ever shall be, world without end. Amen.
The Jesus Prayer (Orthodox tradition)
Lord Jesus Christ, Son of God, have mercy on me, a sinner.
The main Christian churches
| Church family | Approx. members | Leadership | Key features |
|---|---|---|---|
| Catholic Church | about 1.4 billion | The Pope (Bishop of Rome) and bishops | Seven sacraments; Mass; devotion to Mary and saints. Includes 23 Eastern Catholic churches (e.g. Maronite, Ukrainian, Syro-Malabar). |
| Eastern Orthodox | about 220–260 million | Patriarchs (Constantinople is “first among equals”, Moscow is the largest) | Divine Liturgy, icons, ancient traditions; separated from Rome in 1054. |
| Oriental Orthodox | about 60 million | Coptic, Ethiopian, Eritrean, Armenian, Syriac and Malankara churches | Separated after the Council of Chalcedon (451). |
| Protestant (incl. Anglican, Lutheran, Reformed, Baptist, Methodist, Pentecostal, Evangelical) | about 800 million – 1 billion | Varies by church | Began with the Reformation (1517); emphasise Scripture alone, grace and faith. |
2,000 years of Christian history
Glossary
- Apostle
- “One who is sent” — the Twelve chosen by Jesus, and St Paul.
- Bible
- The holy book of Christians — see Bibles.
- Christ / Messiah
- “Anointed One” — the promised Saviour-King.
- Gospel
- “Good News” — also the four books about Jesus' life.
- Grace
- God's free gift of his love and life.
- Incarnation
- God the Son becoming a human being in Jesus.
- Mass / Liturgy
- The main act of Christian worship, centred on the Eucharist.
- Pope
- From “papa”, father — the Bishop of Rome. See Popes.
- Resurrection
- Jesus rising from the dead on Easter Sunday.
- Saint
- A holy person in heaven. See Saints.
- Trinity
- One God in three Persons: Father, Son and Holy Spirit.
Sources & further reading
- Catechism of the Catholic Church (Vatican) and its Compendium
- Pew Research Center, Global religious landscape 2010–2020 (2025); Vatican Annuarium Statisticum Ecclesiae
- Encyclopaedia Britannica, Christianity; World Council of Churches, Church families
- The Bible: Exodus 20; Matthew 6; Matthew 28:19