A parable is a comparison made between things discordant by nature, under some similitude. For parable is the Greek for a similitude, when we point out by some comparisons what we would have understood. In this way we say an iron man, when we desire that he should be understood to be hardy and strong; when to be swift, we compare him to winds and birds. But He speaks to the multitudes in parables, with His usual providence, that those who could not take in heavenly things, might conceive what they heard by an earthly similitude.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).