The Mirror of Erised

Did you notice?

A mirror shows a desired thing, not a true future, and the inscription is a reversed sentence the book lets you decode. Harry finds his parents. That image is kindness and a trap. A headmaster’s warning — the mirror does not give knowledge or truth — is the chapter’s thesis, delivered after the longing has worked.

Foreshadowing

Desire as a security system returns whenever an object should only be taken by someone who wants it for the right reason. The stone’s hiding place is this idea turned into a lock.