As resemblance lies at the foundation of the metaphor, it may be called an abbreviated form of comparison, the thing with which the comparison is made being directly predicated of that which is compared.  Thus, when we say:  A sluggard is vinegar to the teeth and smoke to the eyes of those who send him, we have a metaphor, the sluggard being directly called vinegar and smoke.  But if we say:  “As vinegar to the teeth, and as smoke to the eyes, so is the sluggard to them that send him” (Prov. 10:26), we have a comparison, and the language ceases to be tropical.  The metaphor is thus a more vivid form of expression than the comparison.

A common mode of comparison in the book of Proverbs is simply to put together the object compared and the thing or things with which it is compared, thus:  “A whip for the horse, a bridle for the ass, and a rod for the fool’s back” (chap. 26:3); that is, As a whip is appropriate for, the horse, and a bridle for the ass, so is a rod for the fool’s back.  Again, “Where there is no wood the fire goeth out, and where there is no tale-bearer the strife ceaseth” (Prov. 26:20); “Charcoal to live coals, and wood to fire; and a man of strife to kindle strife” (Prov. 26:  21); “Silver dross spread over an earthen sherd—­burning lips [lips glowing with professions of love] and a wicked heart” (Prov. 26:  23); in all which cases our version has supplied particles of comparison.

(2.) An allegory is the narrative of a spiritual transaction under the figure of something lower and earthly, the lower transaction representing directly the higher.  We have in the eightieth Psalm an exquisite example of the allegory:  “Thou hast brought a vine out of Egypt:  thou hast cast out the heathen and planted it.  Thou preparedst room before it, and didst cause it to take deep root, and it filled the land.  The hills were covered with the shadow of it,” etc. (ver. 8-16); where the transfer of the Israelitish people from Egypt to the land of Canaan, with their subsequent history, is described under the figure of a vine.

The metaphor and allegory have this in common, that the foundation of both is resemblance, and in both the lower object is put directly for the higher.  Yet the metaphor cannot be properly called a condensed allegory, nor the allegory an extended metaphor; for it is essential to the allegory that it have the form of a narrative, and that it contain real history—­in the case of prophecy it may be future history—­under a figure.  Hence it admits of indefinite extension, as in the “Pilgrim’s Progress;” and we may add the Canticles, which the Christian church from the earliest times has regarded as an allegory of which the subject is, in Old Testament language, God and his covenant people, but, according to the representation of the New Testament, Christ and his church.