This could be one:

Neither Philip II nor his son Alexander the Great even attempted to conquer Sparta: it was too weak to be a major threat that needed to be eliminated, but Spartan martial skill was still such that any invasion would have risked potentially high losses. Even during her decline, Sparta never forgot its claims on being the "defender of Hellenism" and its Laconic wit. An anecdote has it that when Philip II sent a message to Sparta saying "If I enter Laconia, I will level Sparta to the ground," the Spartans responded with the single, terse reply: "If."