Both the Scripture passages on which it's based and the piece by David C. McCasland are worth reading, pondering, and praying about.
One of the primary temptations the devil, the world, and our sinful selves hold out to us is this notion that whatever goodness we may thing we possess is intrinsic to our own natures and personalities. But my observation is that the moment we think we're righteous, we're in deep trouble. No one is more prone to undertaking a whole passel of rotten thoughts and entertaining more poisonous thoughts than those who think themselves constitutionally incapable of wrongdoing.
Hitler never second-guessed himself. Saint Paul did.
Jesus had some interesting things to say along these lines:
“Do not judge, so that you may not be judged. 2For with the judgment you make you will be judged, and the measure you give will be the measure you get. 3Why do you see the speck in your neighbor’s eye, but do not notice the log in your own eye? 4Or how can you say to your neighbor, ‘Let me take the speck out of your eye,’ while the log is in your own eye? 5You hypocrite, first take the log out of your own eye, and then you will see clearly to take the speck out of your neighbor’s eye." (Matthew 7:1-5)Do those words make you feel a bit uncomfortable? Me too. Especially when I consider the enormous logs of sin I've often gathered in my own eyes, even in the three-decades-plus that I've tried to follow Jesus. "So if you think you are standing, watch out that you do not fall."