What is a parable? A parable is a flexible term; it can stretch to include a variety of things. But, at its base, a parable is a metaphorical story or saying. By using a metaphor, a parable compares two things. It describes one thing by likening it to something else.
As the author comes to the final warning passage in Hebrews 12:25–29, it helps if we see its apparent severity in the light of the principle that the indicatives of grace give rise to the imperatives of obedience. “You have not come … But you have come” (Heb. 12:18, 22).