ectypal.net

...the Westminster Confession declares that Scripture itself is the guide to its own interpretation. This point is implied in the declaration that Scripture is the ultimate norm of doctrine and that it states clearly in one place what is unclear in another, a point not made explicitly in any of the great Reformed confessions prior to Westminster. Here, the hermeneutical principle of the analogia fidei, previously developed only in theological systems, attains confessional status. Scripture is the infallible rule of faith and life—and “the infallible rule of interpretation of Scripture is the Scripture itself.”