object lesson

Definition from Wiktionary, a free dictionary

[edit] English

[edit] Noun

object lesson

1. a lesson taught (especially to young children) using a familiar or unusual object as a focus
2. an example that typifies a principle
3. a punishment intended as a deterrent to others
4. (idiomatic) Anything used an example or lesson which serves to warn others as to the outcomes that result from a particular action or behavior, as exemplified by the fates of those who followed that course.

   Let that be an object lesson to him.