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What Does Scriptural Sufficiency Mean?

Scripture is the only sufficient, certain, and infallible rule of all saving knowledge, faith, and obedience according to the Reformed confessions.

Such an understanding of Scripture has been confessed by Protestant Christians since the Reformation. However, our understanding of sufficiency has corroded over the years. There has been a slippage between how the Reformers thought about sufficiency and how many modern Christians do.

When the doctrine of sufficiency is being wielded as a weapon against areas as widely divergent as Critical Race Theory to Classical Theism you know you’ve found an issue in need of clarification.

So, what does it mean to say Scripture is sufficient?

Let’s Start with Some Questions

Let’s start with a few questions to orient ourselves.

Is Scripture sufficient for changing the oil on my pickup truck? I think most would say no. Maybe there are general principles to work hard and not lose my temper when I cut my hand but there isn’t an instruction list for how to properly do this.

So, let’s try another one. Is Scripture sufficient for determining the validity of the law of non-contradiction? I think most would say sort of. But this is more difficult than the first.

Now, a more difficult question. Is Scripture sufficient for determining our thoughts on ethical topics like transhumanism? I think most would say yes and no. While the Bible may not address the modern technological challenges we face, there are general Christian principles that guide us as we navigate these challenges.

Finally, let’s take one that is right at the center of our faith as Christians. Is Scripture sufficient for the metaphysics of the incarnation? Yes, but we have to admit no verse in the Bible directly says that there are two natures that are inconfusedly, unchangeably, indivisibly, inseparably united. The Bible does not use the terminology of two natures that are inseparable.

Does this mean it isn’t “in” the Bible? Does this mean Scripture is insufficient?

These examples illustrate two related but crucial questions regarding what sufficiency is supposed to mean:

  1. What does it mean for something to be “in” Scripture?
  2. Does the sufficiency of Scripture require all things exhaustively to be in Scripture?

While most would agree that the Bible doesn’t contain an instruction manual for oil changes, many find it difficult to understand scriptural sufficiency when it comes to topics like logic, transhumanism, and incarnation.

So, what are we to make of these questions?

Turning to the Wisdom of Earlier Christians

I think it’s helpful to begin by remembering how the Reformed confessions understand the nature of sufficiency. Take the very beginning of the Second London Confession of Faith 1.1:

The Holy Scripture is the only sufficient, certain, and infallible rule of all saving knowledge, faith, and obedience, although the light of nature, and the works of creation and providence do so far manifest the goodness, wisdom, and power of God, as to leave men inexcusable; yet they are not sufficient to give that knowledge of God and His will which is necessary unto salvation.

There are several aspects to unpack here. Instead of beginning by explaining what they do mean I am going to start by explaining what they don’t mean. Sometimes one of the best ways to understand something is to understand what it’s not. So, notice what the confession does not say:

  • Because Holy Scripture is the only sufficient, certain, and infallible rule of all saving knowledge, faith, and obedience, therefore there are no insufficient, uncertain, and fallible subordinate rules.”
  • “Holy Scripture is the only sufficient, certain, and infallible rule of all saving knowledge, faith, and obedience whatsoever.”
  • “The light of nature, and the works of creation and providence do not manifest the goodness, wisdom, and power of God.”

Each of these misinterpretations is quite common.

So common, in fact, that two of the greatest Protestant theologians in Francis Turretin (1623-1687) and Herman Bavinck (1854-1921) address them as well.

They too found ample misunderstandings of the sufficiency of Scripture. They provide laundry lists of what sufficiency doesn’t mean. Three of them relate directly to the most common misunderstandings today. They argue that:

  1. Sufficiency doesn’t mean that Scripture contains everything done or said by Christ. John 20:30 says as much.
  2. Sufficiency doesn’t mean that everything is taught word for word in Scripture. Many things are to be deduced by inference.
  3. Sufficiency doesn’t mean that it contains everything exhaustively related to the Christian faith—only that it contains matters necessary to salvation (e.g. the articles of faith).[1]

So, sufficiency doesn’t mean that Scripture contains all possible knowledge—either word for word or implicitly. It certainly doesn’t contain knowledge about how molecular biology works or the compression ratio of premium and regular unleaded fuel.

The Reformed tradition provides conceptual clarity here.

Part of the reason they were able to properly locate the doctrine of sufficiency is because they sought to distinguish between various epistemological principles.

First, the Spirit himself works as the ontological principle of knowledge. He is the ultimate bedrock.

Second, Scripture is the infallible external cognitive principle of knowledge.

But there remains a third principle of knowledge: the internal cognitive principle where the Spirit causes knowledge to be received, contemplated, and confessed via various sources.[2] The sufficiency of Scripture does not invalidate this third principle.

Rational contemplation in faith is a necessary means for knowledge. But this does not mean it is either the first principle from which doctrines of faith are tested and proved or the foundation from which they are built.[3]

It is the Spirit himself as ontological principle and Scripture as infallible external cognitive principle that fulfill these roles.

Senses of Sufficiency

But what does sufficiency mean? It means that we have a single final authoritative rule for all matters of saving knowledge, faith, and obedience. Unlike Roman Catholicism, we do not have an incomplete revelation that needs alternative means to supplement its lack.[4] It means that Scripture is the norming norm for all saving knowledge, faith, and obedience. It is the final arbiter of truth for all saving knowledge, faith, and obedience. It is the final rule for all saving knowledge, faith, and obedience.

As a sufficient rule, it means that nothing can supersede Scripture. If something disagrees with Scripture, it is wrong. As to sufficiency in content, it means that Scripture is the sufficient rule in a limited scope. It relates to all saving knowledge, faith, and obedience. It does not speak to all areas. There is non-saving knowledge that can be found outside of Scripture.

Consider the Second London Confession of Faith 1.6 where it offers further clarity:

The whole counsel of God concerning all things necessary for His own glory, man’s salvation, faith and life, is either expressly set down or necessarily contained in the Holy Scripture: unto which nothing at any time is to be added, whether by new revelation of the Spirit, or traditions of men.

Nevertheless, we acknowledge the inward illumination of the Spirit of God to be necessary for the saving understanding of such things as are revealed in the Word, and that there are some circumstances concerning the worship of God, and government of the church, common to human actions and societies, which are to be ordered by the light of nature and Christian prudence, according to the general rules of the Word, which are always to be observed.

The confession provides answers to both the nature of sufficiency and the content of sufficiency. Let’s take them in turn.

The Nature of Sufficiency

The first question to be considered is “what do we mean by something being “in” the Bible?”—this relates to the nature of sufficiency.

As with most theology, the answer is not simplistic. Theology requires us to distinguish between various senses of sufficiency. Francis Turretin is a good guide at this juncture. He distinguishes between the form or substance of Scripture and the specific literal words of Scripture.

Only the actual words are absolutely contained in Scripture. But while many things are not recorded literally in the words of the Bible, they are contained in its form or substance. Within the substance of Scripture, things are contained “in them really” or they are “not doctrines necessary to salvation” or “false and counterfeit” doctrines.[5]

It is the terminology of substance and form wherein the Reformed confessional “good and necessary consequence” methodology fits (e.g., “expressly set down or necessarily contained”).

These consequences from Scripture, though they are not absolutely “in” Scripture, are either innate (virtually contained) or implied and carried into it. Some consequences are proximate, necessary, and plain but others are remote, probable, and obscure.[6] But the Reformed tradition has understood these to be “in” Scripture—even if they require external philosophical contemplation.

It is the wooden sense of “in” the Bible (absolute/word-for-word only) that heretics have often used to twist the substantial meaning of Scripture while claiming to be following what the Bible teaches.

You see this with the Eunomians in the early church and the Socinians in the Reformation. For example, Francis Turretin argues at length against the Socinians:

Our controversy here is with the Socinians who deny the existence of any such natural theology or knowledge of God and hold that what may appear to be such has flowed partly from tradition handed down from Adam, and partly from revelations made at different times. The orthodox, on the contrary, uniformly teach that there is a natural theology, partly innate (derived from the book of conscience by means of common notions) and partly acquired (drawn from the book of creatures discursively).[7]

His problem with the Socinians is restricting the knowledge of God. And it seems this problem isn’t new.

Basil (329–379) and Gregory of Nazianzus (329–390) faced a similar challenge. Basil confesses his frustration with those critiquing Pro-Nicene theology:

Since whatever the theologians seem to have recorded about the substance of God has been expressed in figurative language or even in allegories, the words transport us to other notions. Hence if someone should contentiously stand by the mere letter, taking it in its obvious interpretation without duly examining it, he has strayed into the myths of the Jews [Ti 1.14] and silly old wives’ tales [1 Tm 4.7], and he will grow old in abject poverty, devoid of worthy concepts about God.[8]

Gregory similarly calls these thinkers “textual vandals” that use their simplistic notions to “rob the written word” of its sense.[9] He argues in a similar fashion:

Time and time again someone repeats the argument about not being in the Bible. Yet we are dealing here not with a smuggled-in alien, but with something disclosed to the consciousness of men past and present. The fact stands already proved by a host of people who have discussed the subject, all men who read the Holy Scriptures not in a frivolous, cursory way, but with penetration so that they saw inside the written text to its inner meaning.[10]

The constant refrain among the false teachers is to “show us the express words or we cross them out as unscriptural.”[11] But Gregory argues that you cannot be “dreadfully servile to the letter.”[12] There must be a place for biblical teaching that is implicitly, though not explicitly, located in the Bible.

The Scope of Sufficiency

Now, what about whether the sufficiency of Scripture requires all things exhaustively to be in Scripture? There are really two questions embedded within this one.

First, does Scripture contain absolutely everything about the world? Most are comfortable answering this as no. Scripture doesn’t contain how molecular biology works or the compression ratio of premium unleaded fuel. It doesn’t teach me how to change the oil on my truck. Fine and good.

But what about whether or not everything helpful for Christians to know is contained in Scripture? It might seem anti-Protestant to suggest there are useful truths in nature that are not found either explicitly (e.g., absolutely and word-for-word) or implicitly (e.g., by good and necessary consequence) in Scripture.

But here again, Reformational Protestants may surprise us. As the Second London Confession explicitly claims, there are some things that are ordered by the light of nature and Christian prudence.

The sufficiency of Scripture is about matters of saving knowledge, faith, and obedience. That modifier is critical. It could have excluded it and universalized the claim. But it didn’t.

And this is good since God is infinite. If everything about him could be contained in a book he would no longer be infinite. As Gregory of Nazianzus reminds us, “No one yet has discovered or ever shall discover what God is in his nature and essence.”[13]

Summing Up

The sufficiency of Scripture is a beautiful doctrine. It comforts us because we needn’t worry that we will fail to have all knowledge necessary to know God and obey him. It encourages us because we can grow in our faith without needing a multi-million-dollar library.

But it is liable to be abused like any other doctrine. And it’s liable to be misunderstood in both liberal and conservative directions. We can end up rejecting it or we can end up expanding it beyond its proper scope.

The truth of sufficiency is that the Bible is the only sufficient, certain, and infallible rule. But there remain other insufficient, uncertain, fallible subordinate rules.


[1] Francis Turretin, Institutes of Elenctic Theology, ed. James T. Dennison, trans. George Musgrave Giger (Phillipsburg, NJ: P&R, 1994), 1:135; Herman Bavinck, Reformed Dogmatics, ed. John Bolt, trans. John Vriend (Grand Rapids: Baker Academic, 2003), 1:488.

[2] Michael Allen and Scott R. Swain, Reformed Catholicity: The Promise of Retrieval for Theology and Biblical Interpretation (Grand Rapids: Baker Academic, 2015), 31–32.

[3] Turretin, Institutes of Elenctic Theology, 1:24.

[4] Bavinck, RD, 1:481.

[5] Turretin, Institutes of Elenctic Theology, 140.

[6] Turretin, 1:38.

[7] Turretin, 1:6.

[8] Basil, Against Eunomius, trans. Mark DelCogliano and Andrew Radde-Gallwitz (Washington, D.C.: The Catholic University of America Press, 2011), 1.14.

[9] Gregory of Nazianzus, On God and Christ: The Five Theological Orations and Two Letters to Cledonius, trans. Frederick Williams and Lionel R. Wickham (Crestwood, NY: St. Vladimir’s Seminary Press, 2002), Oration 31, 1.

[10] Gregory of Nazianzus, Oration 31, 21.

[11] Gregory of Nazianzus, Oration 31, 23.

[12] Gregory of Nazianzus, Oration 31, 24.

[13] Gregory of Nazianzus, Oration 28, 17.