The Catholic Church teaches that individuals can be complicit in another person's sin in various ways. These "Nine Ways of Being Accessory to Another's Sin" highlight the different means by which one may participate in or facilitate someone else's wrongdoing:
By Counsel: Advising or encouraging someone to commit a sin.
By Command: Ordering or directing someone to commit a sin.
By Consent: Giving approval or agreeing with someone's sinful actions.
By Provocation: Provoking, enticing, or leading someone to sin.
By Praise or Flattery: Praising or flattering someone for their sinful actions, thereby encouraging them.
By Concealment: Hiding or covering up someone’s sin, preventing it from being known or corrected.
By Partaking: Sharing in or taking part in another's sin.
By Silence: Failing to speak out against or warn someone about their sin when obligated to do so.
By Defense of the Ill Done: Defending or justifying another's sinful actions.
These ways of being accessory to another's sin emphasize the importance of not only avoiding sin oneself but also avoiding actions that support or enable sin in others. The Catholic Church encourages individuals to lead others towards good and away from sin, promoting moral responsibility and accountability within the community.