What were C.S. Lewis's personal religious views?

Lewis was raised in a church-going family in the Church of Ireland. He became an atheist at 15, though he later described his young self as being paradoxically "very angry with God for not existing".[25]

His early separation from Christianity began when he started to view his religion as a chore and as a duty; around this time, he also gained an interest in the occult, as his studies expanded to include such topics.[26] Lewis quoted Lucretius (De rerum natura, 5.198-9) as having one of the strongest arguments for Atheism:[27]Nequaquam nobis divinitus esse paratamNaturam rerum; tanta stat praedita culpa"Had God designed the world, it would not beA world so frail and faulty as we see."

Lewis's interest in the works of George MacDonald was part of what turned him from atheism. This can be seen particularly well through this passage in Lewis's The Great Divorce, chapter nine, when the semi-autobiographical main character meets MacDonald in Heaven:

...I tried, trembling, to tell this man all that his writings had done for me. I tried to tell how a certain frosty afternoon at Leatherhead Station when I had first bought a copy of Phantastes (being then about sixteen years old) had been to me what the first sight of Beatrice had been to Dante: Here begins the new life. I started to confess how long that Life had delayed in the region of imagination merely: how slowly and reluctantly I had come to admit that his Christendom had more than an accidental connexion with it, how hard I had tried not to see the true name of the quality which first met me in his books is Holiness.[28]

He slowly re-embraced Christianity, influenced by arguments with his Oxford colleague and friend J. R. R. Tolkien, whom he seems to have met for the first time on 11 May 1926, and by the book The Everlasting Man by G. K. Chesterton. He fought greatly up to the moment of his conversion, noting that he was brought into Christianity like a prodigal, "kicking, struggling, resentful, and darting his eyes in every direction for a chance to escape."[29] He described his last struggle in Surprised by Joy:

You must picture me alone in that room in Magdalen, night after night, feeling, whenever my mind lifted even for a second from my work, the steady, unrelenting approach of Him whom I so earnestly desired not to meet. That which I greatly feared had at last come upon me. In the Trinity Term of 1929 I gave in, and admitted that God was God, and knelt and prayed: perhaps, that night, the most dejected and reluctant convert in all England.[30