Why do we still use fables from ancient greece today?

Fable is a literary genre: a succinct fictional story, in prose or verse, that features animals, legendary creatures, plants, inanimate objects, or forces of nature that are anthropomorphized (given human qualities, such as the ability to speak human language) and that illustrates or leads to a particular moral lesson (a "moral"), which may at the end be added explicitly as a pithy maxim or saying.

powers  are  denied  to the  national governmentin three distinct ways: some  powers, such as the  power  to levy duties on exports or prohibit the freedom of religion, speech, press, or assembly, are expressly  denied  to the  national government  in the  constitution.