Custom can neither arise from nor be destroyed by a wrong.

Explanation

An unlawful practice, no matter how long continued, never ripens into a binding custom — illegality at the root destroys the claim.

Where this applies

• An illegal practice has been going on for years, and someone claims it has become custom.
• A party argues that a longstanding violation of law has ripened into an enforceable right.

See also

• 1.3.4 A custom, however great its authority, should never prejudice manifest truth.
• 7.7.1 One wrong does not excuse another.