C.S. Lewis on Faith, Reason, and Real Christianity

10 Well-Known Quotes from C.S. Lewis’ Mere Christianity

1. “You don’t have a soul. You are a soul. You have a body.”
   (Paraphrased from Lewis’s letters, often quoted to express his view of eternal identity.)
2. “I believe in Christianity as I believe that the sun has risen, not only because I see it but because by it I see everything else.”
3. “If I find in myself a desire which no experience in this world can satisfy, the most probable explanation is that I was made for another world.”
4. “Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important.”
5. “A man who was merely a man and said the sort of things Jesus said would not be a great moral teacher. He would either be a lunatic — or else he would be the Devil of Hell. You must make your choice.”
6. “No man knows how bad he is till he has tried very hard to be good.”
7. “Faith … is the art of holding on to things your reason has once accepted, in spite of your changing moods.”
8. “We are half-hearted creatures, fooling about with drink and sex and ambition when infinite joy is offered us.”
9. “God cannot give us a happiness and peace apart from Himself, because it is not there. There is no such thing.”
10. “To be a Christian means to forgive the inexcusable, because God has forgiven the inexcusable in you.”

Book Review: Mere Christianity by C.S. Lewis

Overview

Mere Christianity began as a series of BBC radio talks during World War II. Lewis — an Oxford professor and former atheist — wanted to explain and defend the core truths of the Christian faith in a way that reached ordinary listeners. He called this shared foundation “mere Christianity,” meaning the basic truths common to believers across denominations.

The book unfolds in four main parts:

• Right and Wrong as a Clue to the Meaning of the Universe
• What Christians Believe
• Christian Behaviour
• Beyond Personality: First Steps in the Doctrine of the Trinity

Key Themes

1. A Moral Law Points to a Moral Lawgiver

Lewis begins with the shared human sense of right and wrong. We may differ about details, but we all appeal to a moral standard. That moral awareness, he argues, is evidence of a moral Lawgiver — God Himself.

2. Who Jesus Really Is

Lewis’s famous “liar, lunatic, or Lord” argument insists that Jesus cannot be reduced to a mere teacher. His claims force a real decision: either He was deluded or He was divine.

3. Christian Living Is Not Just “Being Nice”

Lewis writes practically about forgiveness, pride, charity, and moral growth. Christianity, he says, is not about becoming slightly better people — it’s about transformation by God’s Spirit.

4. Becoming New

God’s goal, Lewis explains, is to turn us from “toy soldiers” into living sons and daughters. The process can be painful but leads to true joy and real life.

Style and Voice

Lewis writes as a patient friend, using vivid analogies — fleets of ships, painters, mirrors — to illuminate deep truths. His tone is warm, logical, and compassionate, welcoming both skeptics and believers.

Why It Still Matters

Decades later, Mere Christianity continues to shape discussions of faith and reason. It bridges intellect and devotion, helping readers see Christianity not as blind belief but as a rational and heartfelt trust in truth.

You can explore or purchase the book here: Get Mere Christianity on Amazon .

Gentle Critiques

Some of Lewis’s examples reflect his 1940s context, yet his reasoning and sincerity remain timeless. His central invitation — “Come and see what Christianity really claims” — still rings true.

Closing Thought

Mere Christianity is not merely argument but invitation. Lewis opens the door to faith with reason and love. As he writes, “The hardness of God is kinder than the softness of men, and His compulsion is our liberation.”