I had the privilege of studying the parables in seminary with Dr. William Farmer, who, at the time, was one of the foremost New Testament scholars in the world, and I'll never forget the first lesson Dr. Farmer taught us. He said, "A parable is a simple story, using concrete imagery, to make a single point."

Simple as that: "A parable is a simple story, using concrete imagery, to make a single point." Parables are not intended to be allegories (where one thing represents another). They're not to be interpreted metaphorically. They're not similes, or analogies, or paradigms, or riddles. A parable is a simple story, using concrete imagery, to make a single point - and, in the case of Jesus' parables, a single point about the nature of the Kingdom of God.