The clarity of Scripture (also called perspicuity) is the doctrine that while not all things in Scripture are equally plain, those things necessary to be known, believed, and observed for salvation are so clearly propounded that not only the learned but the unlearned, in a due use of the ordinary means, may attain a sufficient understanding of them. ^[raw/en/wcf-ch01-s07.md]
Psalm 119:105 declares: "Thy word is a lamp unto my feet, and a light unto my path." The psalmist does not say Scripture is a floodlight illuminating everything at once, but a lamp — sufficient to see the next step. God has not promised to answer every curiosity but to show the way to walk.
Psalm 19:7 makes an even more extraordinary claim: "The testimony of the Lord is sure, making wise the simple." The Hebrew pethi (simple) describes the inexperienced, the untaught. And what does the Word do for such a person? It makes them wise — with wisdom leading to salvation.
Deuteronomy 30:11-14 (echoed in Romans 10) affirms that God's word is not far off: "the word is very nigh unto thee, in thy mouth, and in thy heart, that thou mayest do it."
The Confession opens with the honest acknowledgement that "all things in Scripture are not alike plain in themselves, nor alike clear unto all," drawing from 2 Peter 3:16 where Peter admits Paul's letters contain "some things hard to be understood." ^[raw/en/wcf-ch01-s07.md]
But the difficulty never falls where salvation is at stake. As Thomas Watson writes: "The Scripture is a garden in which there is not only the tall cedar of lofty mystery, but the hyssop of plain truth, which the weakest Christian may gather." There is milk for babes and meat for strong men.
The Divines were answering two enemies. Rome taught that the Bible is a dark book needing the church's magisterium to interpret it. The Enthusiasts claimed the Spirit speaks inwardly apart from the written Word. Against both, the Confession insists that Scripture is clear in its essential message — the way of life is so clearly pointed out that "the wayfaring man, though a fool, shall not err therein" (drawing from Isaiah 35:8). ^[raw/en/wcf-ch01-s07.md]
Calvin was fierce against the Roman claim: "What, then, is the purpose of the Scripture if it is not to be understood? If the Spirit has so spoken that He cannot be understood, He has been a mocker of men rather than a teacher."
The clarity of Scripture does not promise effortless understanding. The "due use of the ordinary means" includes: the public reading of Scripture, faithful preaching, diligent private study, mutual instruction of believers, comparing Scripture with Scripture, and humble dependence on the Holy Spirit.
Francis Turretin distinguishes claritas externa (the external clarity of the text) from claritas interna (the internal clarity when the Spirit illumines the reader). The sun may be shining, but the blind do not see it.
This doctrine is intimately connected to sufficiency-of-scripture: a full treasury that is locked is no comfort to the poor man. It also grounds scripture-interprets-scripture: because Scripture is clear in its essential teachings, the clear passages can interpret the obscure. The ordinary believer, with the Spirit's help and the whole Bible in view, can understand everything necessary for salvation.