Many years ago at a Southern New England Presbytery (PCA) meeting I heard a preacher commit the unpardonable sin: He said and I quote, "Not everything Reformed is biblical." This, of course, amounted to blasphemy in that venue and the poor pastor suffered severe ridicule for his transgression. Despite all of our post-Reformation blather about adherence to the Bible alone, sola scriptura remains something ideal, rather than real. It is strictly a conceptual goal, albeit one certainly well worth pursuing, but theological tradition usually charts the trajectory of doctrinal development—not Scripture. If you think I am overstating the case then tell me, why do creeds and confessions so obviously constitute the authoritative criteria of orthodoxy within the Calvinistic community? The typical answer to my question is that these expressions of faith simply function as summary statements of what God's Word truly teaches. Perhaps, but more often than not they also perform double duty as an inerrant hermeneutic. Come up with a conclusion different from, say, the Heidelberg or Westminster interpretation and you will suddenly find yourself outside the camp. It makes no difference if your perspective is more faithful to the authorial intent of the passage because "Reformed and always reforming" is merely a slogan, not a modus operandi. You are a heretic if you fail to color inside the lines.
I am hardly opposed to sola scriptura. Precisely the opposite, in fact; I embrace the concept without hesitation or reservation. But has anybody in the entire history of interpretation actually practiced it? The answer is a resounding, astounding, "No!" Input determines output: Therefore, whereas sola scriptura is an essential principle, its execution is potentially fallible. Nobody is neutral in their approach to divine revelation. Whatever cultural, historical, personal and doctrinal input an interpreter plugs into the scriptural text inevitably skews the exegetical output, which in turn affects the contours of both biblical and systematic theology. Contemporary Reformed interpreters seem to think they and their forefathers are infallible, yet I remain skeptical of such gnostic arrogance.
I sincerely want the Bible to be the exclusive arbiter of all that I believe, but I know that desire will never be completely fulfilled while sin still darkens my ability to understand and apply God's wonderful Word. Thus, for a very specific reason, I am wholly committed to pursuing theology within creedal parameters despite my aforementioned cynicism. And since nobody can successfully escape the influence of dogmatic traditionalism, it seems smart just to pick whatever historical option exalts God and debases man; Reformed confessionalism looks like the best bet to me. Doing theology within a confessional context is an act of humility. It is an admission of my own propensity for idiosyncratic interpretations and consequently a plea for the checks and balances provided by the Holy Spirit via the corporate consensus of theocentric Protestant voices down through the ages. Although creeds and confessions are not inerrant like the Reformed guild believes—despite its hypocritical protestation of "Reformed, and always reforming"—they necessarily bring me much closer to sola scriptura than I could all by myself.