Mike was unpleasant after he passed a certain point. I liked to see him hurt Cohn. I wished he would not do it, though, because afterward it made me disgusted with myself. That was morality; things that made you disgusted afterward. pp.The Sun Also Rises pp. 148–149
Jake is partially right here, but he does not have a steady moral compass despite being nominally religious. But he is aware of conscience. He is aware of sin’s affect on the soul; though, being aware of something and heeding it are two different things.
Yet the danger here is that Jake’s sole moral compass is how something makes him feel—afterward. But humans are easily deceived into not feeling that same something during the act of sin and in searing our consciences to feel nothing afterward as well. And if that doesn’t happen, we can easily explain away the feelings or rationalize why this time it’s ok. Letting one’s feelings be the guide to our morality is like having one of those dime-store plastic compasses whose needle is slightly bent and struggles to find true north.
And because this is the usual lot of man, we need something more stable to base morality on. We need something more stable than what disgusts us, more stable, even, than what disgusts the majority. The majority, after all, is made up of people walking around with cheap compasses.
No, our morality must come from a set standard, an unchanging code, a guide created by the one who created us. For only our creator knows us well enough to know what is actually good for us. And so it is to God and his Word that we must turn for truth and a clear path that allows us to wake in the morning not disgusted by our actions the night before.