In his Introduction to Old Testament Theology: A Canonical Approach, John Sailhamer addresses the literal sense (sensus literalis) of the text and proposes that the literal sense of Scripture may also function as the spiritual sense (sensus spiritualis).
As part of the overall proposal for an approach to OT theology offered in this book, we strongly urge the consideration of a return to the notion that the literal meaning of the OT may, in fact, be linked to the messianic hope of the pre-Christian, Israelite prophets. By paying careful attention to the compositional strategies of the biblical books themselves, we believe in them can be found many essential clues to the meaning intended by their authors—clues that point beyond their immediate historical referent to a future, messianic age. By looking at the works of the scriptural authors, rather than at the events that lie behind their accounts of them, we can find appropriate textual clues to the meaning of these biblical books. Those clues, we also suggest, point to an essentially messianic and eschatological focus of the biblical texts. In other words, the literal meaning of Scripture (sensus literalis) may, in fact, be the spiritual sense (sensus spiritualis) intended by the author, namely, the messianic sense picked up in the NT books. Such a view of the meaning of the OT is quite similar to that of the apostle Paul in Romans 16:25-27. There Paul speaks of the Gospel of Jesus Christ, which, though hidden in ages past, “has now been revealed and made known through the prophetic writings.” Paul notes three things about the Gospel in these verses: (1) it was formerly a hidden “mystery” in “long ages past” (v. 25); (2) it has now been revealed (v. 26); and (3) it is “made known through the prophetic writings” (v. 26).
Sailhamer, John H. (2010-12-07). Introduction to Old Testament Theology: A Canonical Approach (Kindle Locations 2679-2689). Zondervan. Kindle Edition.