John Piper’s Hero: CS Lewis
It is well known that John Piper is a great promoter of writings of C.S. Lewis. 
Piper describes C.S. Lewis thus: ‘He stands as one of the most influential Christians of the twentieth century.’ Indeed, Piper has gone so far as to refer to CS Lewis as his hero. Some have referred to Lewis as the patron saint of evangelicalism.
While in college, Piper grew to love the work of C.S. Lewis. In 1964, when he started his studies at Wheaton College, he was introduced to Lewis’s Mere Christianity. He writes: ‘For the next five or six year I was almost never without a Lewis book near at hand. I think without his influence I would never have lived by life with as much joy and usefulness as I have… I will never cease to thank God for this remarkable man who came onto my path at the perfect moment’ (Don’t Waste your Life, Crossway, 2002, p19-20).
But it was a few years later, in 1986, that he came across Lewis’s book, The Weight of Glory, which had a profound influence on his thinking. ‘I had never in my whole life heard any Christian, let alone a Christian of Lewis’s stature, say that all of us not only seek but also ought to seek our own happiness’ (Desiring God p 20).
In November 2003, Dr John Robbins, Presbyterian theologian and founder of the Trinity Foundation, presented a paper at the annual meeting of the Evangelical Theological Society, Atlanta, Georgia, entitled ‘Did CS Lewis go to heaven?’. The purpose of the provocative title was to draw the attention of the evangelical world to errors in Lewis’s version of the Christian faith.
Robbins made the point that Lewis had no cultural connections with 
Evangelicals, for all his friends were all Anglo-Catholic or Catholic. He concluded that Lewis cannot accurately be called an Evangelical. He said: ‘On point after point, Lewis taught doctrines contrary to Scripture. He denied the inerrancy of Scripture itself; he rejected the doctrine of the substitutionary, penal atonement; he set forth an odd view of the resurrection of the body, to name only three. In locus after locus of Christian theology, Lewis’ views were un-Biblical and Antichristian.’
In December 2005, Christianity Today, under the cover story, ‘CS Superstar’ said that Lewis ‘was anything but a classic evangelical, socially or theologically. He smoked cigarettes and a pipe, and he regularly visited pubs to drink beer with friends. Though he shared basic Christian beliefs with evangelicals, he didn’t subscribe to biblical inerrancy or penal substitution. He believed in purgatory and baptismal regeneration.’
Desiring God 2010 Conference for Pastors
In February 2010, at the Desiring God Conference for Pastors, Piper preached on ‘Learning from the Mind and Heart of CS Lewis: Lessons from an Inconsolable Soul’.
Piper explained why CS Lewis has been so significant for him, even though he is not reformed in his doctrine, and could barely be called an evangelical.
Desiring God National Conference in 2013
At the National Conference 2013, Piper’s address was entitled, 
‘The Romantic Rationalist: God, Life, and Imagination in the Work of C.S. Lewis’. The focus was on ‘the life, heart, and influence of Lewis, celebrating all we’ve learned through him and asking the hard questions of his writing’.
John Piper, in his blind, total devotion to CS Lewis, refers to him as his hero. He freely acknowledges Lewis’s massive influence on the way he sees the world, on his ministry and on his thinking about the Christian faith. He openly acknowledges 
Lewis’s role in the formation of the heretical philosophy of Christian Hedonism.
In 2011 Pastor Laurence Justice preached a sermon entitled, ‘CS Lewis – False Teacher’. He carefully documents Lewis’s Anglo-Catholic sympathies, and is deeply troubled by Lewis’s rejection of the inerrancy of Scripture and his wrong understanding of salvation.