John 10:6

This parable spake Jesus unto them. — Better, this allegory spake Jesus unto them. The word rendered “parable” is the wider word (παροιμία, paroimia) which includes every kind of figurative and proverbial teaching, every kind of speech, as the etymology reminds us, which departs from the usual course (οῑμος, oimos). St. John nowhere uses the word “parable.” The word paroimia occurs again in John 16:25; John 16:29, and once besides in the New Testament; this is in 2 Peter 2:22 (“according to the true proverb”), in a quotation from the Greek version of Proverbs 26:11, where the Hebrew word is mâshal. (Comp. Note on Matthew 13:3, and Trench On the Parables, pp. 8-10.) The discourse of this chapter differs from the true parable, which is a story in which the outer facts are kept wholly distinct from the ideal truths that are to be taught; whereas here the form and the idea interpenetrate each other at every point. It is so in the other so-called “parable” in this Gospel (John 15). Strictly speaking, neither the “Good Shepherd” nor the “True Vine” is a parable. Both are “allegories,” or rather, they are, as there is every reason to think, allegorical interpretations of actual events in the material world, which are thus made the vehicle of spiritual truths. It will follow from this that the interpretation of every point in the history of the material facts (e.g., “the porter” in John 10:3) is not always to be pressed. In the parable the story is made to express the spiritual truth, and with greater or lesser fulness every point in it may have its spiritual counterpart. The outer facts which are allegorised exist independently of the spiritual truth. The fact that they express it at some central points is all that is necessary for the allegory, and greater caution should attend the use of any addition to the interpretation which is given.

But they understood not what things they were... — They of course understood the outer facts, then passing before their eyes, or, in any case, well known to them. What they did not understand was the spiritual truths underlying these phenomena. They must have known His words had some spiritual meaning. They were accustomed to every form of allegorical teaching, and they could not have thought that He was simply describing to them the everyday events of the shepherd’s life. But they who think that they see (John 9:41) are spiritually blind, and cannot understand the elements of divine truth.