Westminster Confession Of Faith: With Introduction And Notes (1881)
Chapter I | Section vii
All things in Scripture are not alike plain in themselves, nor alike clear unto all: 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.
Not all alike plain. Mysteries in doctrine and varying natural capacities in readers are admitted. The perspicuity attributed to Scripture is relative, on the one hand, to the matter treated of e.g., large portions of Ezekiel, Daniel, and Revelation are obscure and on the other, to the condition of the person who reads the Word.
Necessary to be known for salvation. Perspicuity is affirmed absolutely in regard to those truths that constitute the Rule of Faith, that is, the leading doctrines of the Gospel. The knowledge of these being indispensable to all classes of men, each is found expressed in some particular part of Scripture with unmistakable clearness. The Romish Church maintains that Scripture is not in itself intelligible to the people in matters of faith, and insists that only the church tradition can give the true interpretation. What Rome thus affirms of the church and her tradition Protestantism attributes to the individual reader of the Word who uses the ordained means.
The ordinary means. What these means are depends on our idea of the understanding of Scripture, whether we regard it as a merely literal or as a spiritual understanding. To understand the letter of Scripture we must know the language in which we read it, our natural powers must have reached some degree of maturity, and our minds must be unbiased by prejudices and erroneous views. To understand the spirit of Scripture, and so to receive spiritual profit from our reading, we must have spiritual discernment through the indwelling of the Spirit, and even by the spiritual man prayer must be used as a means to secure enlightenment.