If we do not believe in decent behaviour, why should we be so anxious to make excuses for not having behaved decently?
 C. S. Lewis, Mere Christianity (1952). copy citation

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Author C. S. Lewis
Source Mere Christianity
Topic excuse behaviour
Date 1952
Language English
Reference
Note Adapted from a series of BBC radio talks made between 1942 and 1944
Weblink https://www.dacc.edu/assets/pdfs/PCM/merechristianitylewis.pdf

Context

“That is to say, I do not succeed in keeping the Law of Nature very well, and the moment anyone tells me I am not keeping it, there starts up in my mind a string of excuses as long as your arm. The question at the moment is not whether they are good excuses. The point is that they are one more proof of how deeply, whether we like it or not, we believe in the Law of Nature. If we do not believe in decent behaviour, why should we be so anxious to make excuses for not having behaved decently? The truth is, we believe in decency so much—we feel the Rule of Law pressing on us so—that we cannot bear to face the fact that we are breaking it, and consequently we try to shift the responsibility.” source