The protagonist has been instilled with a belief since he was a child: stealing is a craft, not essentially different from carpenters and blacksmiths, it is nothing more than a hand job. The master taught him the rules, taught him to be particular, taught him the "three no-steals" rules, and made him believe that there is a "way" to stealing.
But real life will continue to shatter this logic. Behind every money he steals, there is a living person, and every "beautiful craftsmanship" may crush a family.
The process of the whole book is the protagonist's long awakening from "believing in craftsmanship" to "recognizing sin" to "understanding why the master never washed his hands".
Washing hands in a golden basin is not an epiphany, it is an inevitable outcome after thirty-two years of accumulation of cause and effect.
