A parable is a short and simple story that teaches a religious or moral lesson. The parable of the Good Samaritan and the parable of the Prodigal Son are just two examples of the many parables attributed to Jesus, as recorded in the four gospels.
Parable descends from the Greek parabolē, "a comparison, analogy," from paraballein, "to compare," from the prefix para-, "beside," plus ballein, "to throw." The sense of comparing, or throwing an idea beside another, is at the heart of the word. When you hear a parable, you're meant to use the comparison to learn how to act — the fox's "sour grapes" are compared to your own downgrading of the thing you cannot have.