An example of a metaphor in the prologue of "Antigone" is when the character Ismene says, "The law is strong, we must give in to the law/In this thing, and in worse." The law in this case is a metaphor for the new ruler of Thebes, Creon. Creon has decreed that Ismene and Antigone's brother, Polyneices, should not be given the proper burial rights.
The punishment for going against Creon's decree is death. Antigone vows to give her brother a proper burial anyway, which causes Ismene to try to talk her out of it. In the quote above, Ismene is saying that Creon is strong and that the sisters have to do as Creon demands, even if it means that their brother's "body must lie in the fields, a sweet treasure/For carrion birds to find as they search for food." Antigone eventually buries her brother against the wishes of Creon. When Creon finds out he decides to execute Antigone by burying her alive in a tomb. Creon's son, Haemon, asks his father to forgive his betrothed, Antigone, but Creon refuses and has her placed in the tomb. After confiding with a seer who tells Creon that his actions have angered the gods, Creon decides to release Antigone. However, when he arrives at the tomb, he finds that Antigone has hung herself. Haemon, in a fit of grief, tries to kill Creon but he fails. Haemon then commits suicide and dies holding Antigone. When Creon's wife, Eurydice, hears that her son has killed himself, Eurydice follows suit and commits suicide, leaving Creon alone and in grief.