Parabole (parable) is a compound word made up of a form of the verb ballo (to throw, lay, or place) and the prefix para (meaning alongside of). The idea is that of placing, or laying, something alongside of something else for the purpose of comparison. A spiritual or moral truth would often be expressed by laying it alongside, so to speak, a physical example that could be more easily understood. A common, observable object or practice was used to illustrate a subjective truth or principle. That which was well known was laid alongside that which was not known or understood in order to explain it. The known elucidated the unknown.