Perspicuity/Clarity of Scripture
Westminster Confession of Faith (1.7)
All things in Scripture are not alike plain in themselves, nor alike clear unto all (2 Pet. 3:16); yet those things which are necessary to be known, believed, and observed for salvation, are so clearly propounded, and opened in some place of Scripture or other, that not only the learned, but the unlearned, in a due use of the ordinary means, may attain unto a sufficient understanding of them (Ps. 119:105, 130).
Martin Luther Bondage of the Will
But, if many things still remain abstruse to many, this does not arise from obscurity in the Scriptures, but from [our] own blindness or want [i.e. lack] of understanding, who do not go the way to see the all-perfect clearness of the truth... Let, therefore, wretched men cease to impute, with blasphemous perverseness, the darkness and obscurity of their own heart to the all-clear scriptures of God... If you speak of the internal clearness, no man sees one iota in the Scriptures, but he that hath the Spirit of God... If you speak of the external clearness, nothing whatever is left obscure or ambiguous; but all things that are in the Scriptures, are by the Word brought forth into the clearest light, and proclaimed to the whole world.
Kevin J. Vanhoozer Is There a Meaning in This Text?
To begin with, it is important to note what the clarity of Scripture does not mean. It does not mean, first of all, that interpretation is unnecessary - the biblical meaning will be delivered up by some mystical process of hermeneutical osmosis. Nor does it mean that an autonomous individual can, by employing critical techniques alone, wrest the meaning from the text. Rather, clarity means that the Bible is sufficiently unambiguous in the main for any well-intentioned person with Christian faith to interpret each part with relative adequacy. In the context of the Reformation, the perspicuity of Scripture was the chief weapon for combating the authority of the dominant interpretive community: Rome (pg. 315).
The idea that the Bible is clear does not obviate the need for interpretation but, on the contrary, makes the work of interpretation even more important. The clarity of Scripture means that understanding is possible, not that it is easy. Redeeming the text does not mean reconciling all interpretive conflicts. The clarity of Scripture is neither an absolute value nor an abstract property, but a specific function relative to its particular aim: to witness to Christ. The clarity of Scripture, in other words, does not mean that we will know everything there is to know about the text, but that we will know enough to be able, and responsible, to respond to its subject matter. The clarity of Scripture is not a matter of its obviousness so much as its efficacy; the Bible is clear enough to render its communicative action effective (317).