“Why do you see the speck in your neighbor’s eye, but do not notice the log in your own eye? Or how can you say to your neighbor, ‘Let me take the speck out of your eye’, while the log is in your own eye?” (Matthew 7:3-4)
C. S. Lewis’ “The Screwtape Letters” was published in 1942. The book is written from the perspective of a demon named Wormwood who receives “training” and “encouragement” from his uncle Screwtape. Screwtape is an older and more experienced demon. Screwtape and Wormwood refer to their “Christian” person they are trying to influence as a “patient.”
It is not only a creative take on the Christian faith and discipleship, but very poignant.
While written almost eighty years ago, the message is still relevant today.
Praxis: Faith in Action 
I didn’t find this in my copy of the Screwtape Letters book, so I don’t think C. S. Lewis wrote it.