Allegory (ἀλληγορία) occurs in the Bible only in the participial form, ἀλληγορούμενος, allegorized (Ga 4:24), where the apostle cites the history of the freeborn Isaac and the slave-born Ishmael, and only speaks of it as allegorically applied. Allegories themselves are, however, of frequent occurrence in Scripture.
An allegory has been sometimes considered as only a lengthened metaphor; at other times as a continuation of metaphors. But, according to its original and proper meaning, as shown by its derivation, the term denotes a representation of one thing which is intended to excite the representation of another thing. In most allegories the immediate representation is made in the form of a narrative; and, since it is the object of the allegory itself to convey a moral, not a historic truth, the narrative is commonly fictitious. The immediate representation is understood from the words of the allegory; the ultimate representation depends upon the immediate representation applied to the proper end. The interpretation of the former is commonly called the grammatical or the literal interpretation, although we should speak more correctly in calling it the verbal interpretation, since, in the plainest narratives, even in narratives not designed for moral application, the use of words is never restricted to their mere literal senses. Every parable is a kind of allegory; e.g. in the parable of the sower (Lu 8:5-15) we have a plain narrative — a statement of a few simple and intelligible facts, such, probably, as had fallen within the observation of the persons to whom our Savior addressed himself, followed by the explanation or allegorical interpretation. The impressive and pathetic allegory addressed by Nathan to David affords a similar instance of an allegorical narrative accompanied with its explanation (2Sa 12:1-14). Allegories thus accompanied constitute a kind of simile, in both parts of which the words themselves are construed either literally or figuratively, according to the respective use of them; and then we institute the comparison between the things signified in the former part and the things signified in the latter part. The most frequent error in the interpretation of allegorical representations is the attempt to discover too minute coincidences, or to apply them in all their details. SEE PARABLE.
But allegorical narratives are frequently left to explain themselves, especially when the resemblance between the immediate and ultimate representation is sufficiently apparent to make an explanation unnecessary. Of this kind we cannot have a more striking example than that beautiful one contained in the 80th Psalm, "Thou broughtest a vine out of Egypt," etc. The allegorical delineation of old age by Solomon (Ec 12:2-6) is perhaps one of the finest of the Old Testament. The use of allegorical interpretation is not, however, confined to mere allegory, or fictitious narratives, but is extended also to history or real narratives. And in this case the grammatical meaning of a passage is called its historical, in contradistinction to its allegorical meaning. There are two modes in which Scripture history has been thus allegorized. According to one, facts and circumstances, especially those recorded in the Old Testament, have been applied to other facts and circumstances, of which they have been described as representative. According to the other, these facts and circumstances have been described as mere emblems. The former is warranted by the practice of the sacred writers themselves; for when facts and circumstances are so applied, they are applied as types of those things to which the application is made. But the latter has no such authority in its favor, though attempts have been made to procure such authority. For the same things are there described, not as types or as real facts, but as mere ideal representations, like the immediate representations in allegory. By this mode, therefore, history is not treated as allegory, but converted into allegory — a mode of interpretation that cannot claim the sanction of Paul from the above treatment of the history of Isaac and Ishmael. — Marsh, Criticism and Interpretation of the Bible, Lect. 5. SEE INTERPRETATION.