An important doctrine regarding the Word of God is what is known as the perspicuity of Scripture or, in other words, its clarity. Perspicuity is the teaching that God's Word is so clear that any one reading or hearing it can understand what the Bible teaches about life and salvation. As the Westminster Confession states,
All things in Scripture are not alike plain in themselves, nor alike clear unto all. Yet, those things that are necessary to be known, believed, and observed for salvation are so clearly propounded, and opened in some place of Scripture or another, that not only the learned, but the unlearned, in a due use of the ordinary means, may attain unto a sufficient understanding of them. (WCF 1.7)
The Scriptures themselves testify to this characteristic of God's Word. Its main message is clear even to the lowly. "The law of the Lord is perfect, reviving the soul; the testimony of the Lord is sure, making wise the simple," the psalmist says (Ps. 19:7). God's Word is to be “a lamp to my feet and a light to my path” (Ps. 119:105), giving clear guidance unto salvation and wisdom. Jesus chastised the two men on the road to Emmaus who did not understand the clear teaching of God's Word about Himself, saying, "O foolish men and slow of heart to believe in all that the prophets have spoken! Was it not necessary for the Christ to suffer these things and to enter into His glory?” (Luke 24:25-26)
In his commentary on the Westminster Confession, Robert Shaw states that the clarity of the Scriptures "may be inferred from the fact that their author is God. If he intended them to be a rule of faith and life to men, surely he has adapted them to the understandings of men." So if the Bible is perspicuous, then any preaching from it should be as well. As Charles Hodge said so simply, "The Bible is a plain book."
This truth about the Bible should encourage the type of preaching so well expressed in the Westminster Directory of Public Worship, when it says preaching should be done:
Plainly, that the meanest may understand; delivering the truth not in the enticing words of man’s wisdom, but in demonstration of the Spirit and of power, lest the cross of Christ should be made of none effect; abstaining also from an unprofitable use of unknown tongues, strange phrases, and cadences of sounds and words; sparingly citing sentences of ecclesiastical or other human writers, ancient or modern, be they never so elegant.
It is quite fascinating that the Puritan influence on Westminster upheld plainness in preaching by advocating such things as making sure the least educated could understand it, avoiding using too many references to Hebrew or Greek, and discouraging long quotes.
Upon returning to campus at Reformed Presbyterian Theological Seminary and resuming our daily chapels, I have been greatly encouraged by the liveliness of the preaching. These strange times in which we live have caused the professors to preach with greater urgency, directness, and clarity (or plainness). For a wonderful example of such perspicuous preaching, listen to Dr. David Whitla's message on "Saying Hard Things" based on the story of Ahaziah and Elijah found in 1 Kings 22 and 2 Kings 1.