I did some more reading today on the concept of sensus plenior, which is a hermeneutic principles that historical/grammatical-only interprets often employ upon those NT quotations of the OT that are obvious departures from their OT historical/grammatical context. The justification for sensus plenior is based upon the historical hermeneutic practices of rabbinic Judaism, which employed multiple forms of interpretation, including several that involve a significance beyond the original meaning of the text. This article here explains several of these interpretive principles that match up with sensus plenior. These are:
(1) p’shat (“simple”)—the plain, literal sense of the text, more or less what modern scholars mean by “grammatical-historical exegesis,” which looks to the grammar of the language and the historical setting as background for deciding what a passage means. Modern scholars often consider grammatical-historical exegesis the only valid way to deal with a text; pastors who use other approaches in their sermons usually feel defensive about it before academics. But the rabbis had three other modes of interpreting Scripture, and their validity should not be excluded in advance but related to the validity of their implied presuppositions.
(2) Remez (“hint”)—wherein a word, phrase or other element in the text hints at a truth not conveyed by the p’shat. The implied presupposition is that God can hint at things of which the Bible writers themselves were unaware.
(3) Drash or Midrash (“search”)—an allegorical or homiletical application of a text. This is a species of eisegesis—reading one’s own thoughts into the text—as opposed to exegesis, which is extracting from the text what it actually says. The implied presupposition is that the words of Scripture can legitimately become grist for the mill of human intellect, which God can guide to truths not directly related to the text at all.
(4) Sod (“secret”)—a mystical or hidden meaning arrived at by operating on the numerical values of the Hebrew letters, noting unusual spellings, transposing letters, and the like. For example, two words, the numerical equivalents of whose letters add up to the same amount, are good candidates for revealing a secret through what Arthur Koestler in his book on the inventive mind called “bisociation of ideas.” The implied presupposition is that God invests meaning in the minutest details of Scripture, even the individual letters.
The grammatical/historical-only proponent will often argue (although the author of that article does not) that sensus plenior is reserved for the inspired writers alone (thus denying the Catholic uses of the principle) and thus modern day interpretation must stick to the grammatical-historical approach.
These same folks reject the analogy of faith that seeks to interpret the OT and the NT as one text, with each informing the exegesis of the other. This is, they say, a "spiritualizing" of the text that goes beyond "normal" hermeneutics and is subsequently dangerous because there is no fixed way of determining what is or ought to be "spiritualized."
The rub for those who would reject the analogy of faith and yet accept sensus plenior as a valid method today is that sensus plenior is a "spiritualizing" method when it departs from p'shat. The rub for those who reject the analogy of faith and limit sensus plenior to the NT authors alone face the fact that there are two valid hermeneutics for the NT authors and only one for us. Upon what foundation do they base this distinction? One could infer that NT injunctions against "adding to or taking from" the original word of the apostle could be applied, but this does not seem to be the case, since a sensus plenior interpretation is unpacking the significance of a text and not altering its original meaning. Thus, it would not be a "different" word, although it would be a "fuller" one. There seems to be not indication from the NT that sensus plenior interpretation ceases with the passing of the canon. Indeed, those who accept sensus plenior as applicable for today note that the NT gives no indication that these hermeneutic principles have been annulled.
But is sensus plenior truly a valid form? Those who would argue that the analogy of faith is dangerous should and probably would argue the same for sensus plenior interpretations, since they also fall prey to possible overextension or misapplications of texts. The failsafe is an appeal to consistency with the plain doctrines set forth in Scripture: no interpretation is valid that alters doctrine or departs from it. Those who use sensus plenior under this control seem to have little difference in their hermeneutic from those who employ the analogy of faith, provided one condition: that their interpretations are limited to the redemptive-historical purpose of Scripture. Sensus plenior interpretation that would seek to use Scripture to comment on history since the close of the canon would be a departure from the intention of Scripture itself, which is to present God's revelation of Himself and His purposes in Creation for His own glory.
But what of those who reject both the analogy of faith and the sensus plenior principle for today's interpreters? They must rely upon an argument from silence insofar as they accept sensus plenior for the NT writers and yet reject it for modern exegetes. This seems a very weak position to hold. Secondly, their method of grammatical/historical-only interpretation seems to not only give precedence to history over logic--that is, the Bible must be read as history first, then as a logical whole (which proponents of the analogy of faith would accept as well, since the immediate context precedes the larger)--but they deny a fully logical exegesis and deny the full harmony of the Old and New Testaments (and this despite the fact that any division of Old and New is purely arbitrary). The OT is a book for Jews only except in those passages dealing directly or indirectly with salvation of the Gentiles, whereas the NT is a book for Gentile Christians and converted Jews. But this does not account for the logical unity of Scripture as one message of God.
It is a logical contradiction to assume one message for two people, since those two people, it is argued, have separate eschatological destinies--thus, two distinct messages contained in the same whole. Where does Scripture give warrant for this bifurcation? In the NT we are constantly and consistently told that God has made one people out of two, calling Gentiles into the promise of God having been given full access to all the blessing that are in Christ. The grammatical/historical-only exegete cannot argue that we must stick to this method because it is the method the Bible uses, unless they are also prepared to reject sensus plenior, for it stands as an alternative method employed by the Bible according to some of their proponents. But if the sensus plenior is rejected and the analogy of faith is rejected then what are we to make of those NT uses of the OT that are departures from the historical/grammatical method? What the grammatical/historical-only exegete faces is an insoluble contradiction upon either premise: either (1) they must reject sensus plenior, which leaves them with a list of NT interpretations that contradict their historical/grammatical method, or (2) they must accept sensus plenior for the NT writer only (an argument from silence) and explain the unwarranted assumption of two messages within the one message of God.
On a final note of inquiry, I am curious how those who would accept sensus plenior would explain those NT passages like the one that indicates that Jesus preached the Gospel to Abraham? It does not seem to fit into the rabbinic principles discussed in the article I linked, but it is easily explained by the analogy of faith.
To conclude with my own position, I think that sensus plenior is not only unecessary, but is an implicit denial of sola scriptura insofar as it seeks to attribute rabbinic hermeneutics to the Biblical writers, who expressly claim that their knowledge is from Jesus (who explained the Scriptures to them without formal training) or from the Holy Spirit. Plus it involves an assumption that all of the NT writers would have been familiar with Rabbinical methods of exegesis, which seems doubtful. They did not claim to possess an authoritative interpretation based upon a hermeneutic principle, but upon the revelation of Jesus Christ. Sensus plenior is an attempt to avoid the analogy of faith while accepting the historical/grammatical-only position.
The analogy of faith is adequate and sound because it employs a grammatical/historical approach and it allows the entirely of Scripture as one message of God to one people of God to be taken as a logical whole rather than as two separate logical wholes (which MUST be done if you have two audiences who are receiving different eschatological destinies). The analogy of faith can be misused or misapplied, but this is a specious argument against it, since any method of interpretation, including the grammatical/historical can be misused or misapplied based on numerous factors (a lack of historical/cultural information about the audience or author, an obscure or imprecise grammatical phrasing or idiom, etc.). Those who reject the analogy of faith are really rejecting the logic of Scripture as one message in favor of historizing approach that must have two messages, two peoples, and a self-conflicting hermeneutic.