Definizione e Significato di "a crow is never whiter for washing itself often"

What is the origin of the proverb "a crow is never whiter for washing itself often" and when to use it?

The origin of the proverb "a crow is never whiter for washing itself often" can be traced back to ancient sources, with variations appearing in medieval literature. The proverb emphasizes the idea that no matter how much someone tries to change their outward characteristics, their core nature will remain the same. It serves as a reminder that true change comes from within, and superficial alterations cannot alter a person's fundamental traits.