Introduction
Preparation
Read the bible verses that come with the key doctrines. Then study and meditate on the bible verses and the doctrines. Write down any questions that arise so that we can discuss them in our group.
To help you study, ask yourself these questions as you read:
Question 1
Scripture is sufficient. Mixing it with worldly influences (science, psychology, philosophy, tradition, charismatic experience) distorts the truth. But we have already discussed that these things are not inherently evil and can be useful in their proper place.Where is the line between using something like psychology or tradition as a tool and allowing it to become an authority alongside Scripture?
How would you know if you had crossed that line in your own life?
Question
God’s Word is a complete and sufficient guide, and we do not need to search for a secret word from God or rely on human wisdom alone.When you face a decision or a struggle, where do you actually go first?
Do you open the Book, or do you look for something else? And if you truly believed Scripture was sufficient, what would change about the way you seek guidance?
Introduction
The Bible is sufficient for all matters of faith and practice, and it is the ultimate authority for the believer’s life.
Key Doctrines
The Holy Scripture is the only sufficient, certain and infallible rule of all saving knowledge, faith and obedience. (Isaiah 8:20, Luke 16:29, Ephesians 2:20, 2 Timothy 3:15-17)
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 ordinary means, may attain to a sufficient understanding of them. (2 Peter 3:16, 2 Timothy 3:15-17, 2 Timothy 3:14-17, Psalm 19:7-8, Psalm 119:105, 2 Peter 1:19, Proverbs 6:22-23, Deuteronomy 30:11-14)
Background for Teachers
In Lesson 1 we established that the Bible is God’s Word. In Lesson 2 we established that it cannot fail. Lesson 3 answers the next question: is Scripture enough? The doctrine of sufficiency says yes. The Bible contains everything we need for salvation, for trusting God perfectly, and for obeying Him perfectly. It is not merely a helpful resource among many. It is the only sufficient, certain, and infallible rule of all saving knowledge, faith, and obedience.
The lesson is organized around four topics:
- What Sufficiency Means — The Bible contains everything we need, and adding to it distorts it.
- Sufficient for All of Life — The purpose of Scripture and the purpose of God for the world.
- No Additional Revelation — Scripture is complete, and the test of all claims is Scripture itself.
- Our Responsibility — How to study, how to test, and how to engage those who add to Scripture.
Topic 1: What Sufficiency Means
The sufficiency of Scripture means that the Bible contains everything we need for salvation, for trusting God perfectly, and for obeying Him perfectly. It is not merely a helpful resource among many; it is the only sufficient, certain, and infallible rule of all saving knowledge, faith, and obedience.
If Scripture were not sufficient, it would lack authority and be subject to human additions. This would mean that Jesus, who is the living Word, is not sufficient to build, rule, and keep His church.
Because the Bible is sufficient, the first sentence of the Baptist Confession of Faith begins with: The Holy Scripture is the only sufficient, certain and infallible rule of all saving knowledge, faith and obedience.
Men need saving knowledge to be saved — that is why it is called saving knowledge. Such saving knowledge can only be found in Scripture. This is an emphatic assertion that contradicts any number of popular ideas. Men cannot be saved by following their own religions or philosophies. This is why any worldly influence in the church is so dangerous. Even a minor mixing in with religiosity, tradition, liberalism, humanism, philosophy, psychology, charismaticism, legalism, prosperity preaching, or any other worldly influence will distort the truth of Scripture.
Now when they say to you, “Inquire of the mediums and the spiritists who whisper and mutter,” should not a people inquire of their God? Should they inquire of the dead on behalf of the living? To the law and to the testimony! If they do not speak according to this word, it is because they have no dawn. And they will pass through the land hard-pressed and hungry, and it will be that when they are hungry, they will be angry and curse their king and their God as they face upward. Then they will look to the earth, and behold, distress and darkness, the gloom of anguish; and they will be banished into thick darkness.
Isaiah 8:19-22 (LSB)
The Connection to Lessons 1 and 2
In Lesson 1 we saw that the Bible is God’s Word. In Lesson 2 we saw that it cannot fail. Here in Lesson 3 we see that it is enough. These three doctrines are linked. If Scripture is God’s Word, it cannot fail. If it cannot fail, it is sufficient. The chain holds together.
Discussion
If Scripture is sufficient, why do we so often look elsewhere? The temptation is not usually to deny the Bible outright. It is to add something to it: a tradition, an experience, a technique. The doctrine of sufficiency calls us back to the Book.
Topic 2: Sufficient for All of Life
Why the Bible Has No Gray Areas
As discussed before, God made covenants and God swore by Himself as recorded in Scripture. By doing so, His own Words in Scripture have put His own character, His own name, and His whole existence on the line. Therefore, God will not and cannot allow His infallible Words to be mixed with fallible words of man.
God is Light, and in Him there is no darkness at all.
1 John 1:5 (LSB)
Remember that what Scripture teaches is not just some good tips. They are commands that we must keep. Just as in the army, refusing a legitimate command is a felony that can get you in prison, or refusing to do your duty in your job can get you fired, so are God’s commandments meant to be kept.
If you love Me, you will keep My commandments.
John 14:15 (LSB)
Please note the first part of the sentence Jesus spoke: keeping God’s commandments is unconditionally connected to the love of Christ. A real Christian and follower of Christ is not a legalist.
Do not be unequally yoked with unbelievers; for what partnership have righteousness and lawlessness, or what fellowship has light with darkness? Or what harmony has Christ with Belial, or what has a believer in common with an unbeliever? Or what agreement has a sanctuary of God with idols? For we are a sanctuary of the living God; just as God said, “I will dwell in them and walk among them; And I will be their God, and they shall be My people. Therefore, come out from their midst and be separate,” says the Lord. “And do not touch what is unclean, And I will welcome you. And I will be a father to you, And you shall be sons and daughters to Me,” says the Lord Almighty.
2 Corinthians 6:14 (LSB)
God clearly commands us to be separate, to make clear distinctions between worldly, empty human philosophies and Scripture. We are commanded never, ever to mix worldliness with Scripture because Scripture alone is sufficient.
Are Science, Psychology, Philosophy, and Tradition Inherently Evil?
No, they are not. When you are sick, when you are preparing for an exam, you should pray, but you should also visit a doctor or study. The distinction between human wisdom and authority is authority: a tool serves, an authority rules.
A Line Between Tools and Authority
Psychology, science, and tradition are not evil in themselves. They become dangerous when they stop serving Scripture and start ruling alongside it. The question is not whether you use them. The question is whether you submit to them. A tool in your hand is a servant. A tool on the throne is an idol.
Sufficient for All Aspects of Life?
The Bible does not claim to be a comprehensive guide to astronomy, business, history, or medicine. This is not the purpose of Scripture because it is not the purpose of God for the temporal, fallen world.
The purpose of God for the fallen world is to:
- Display His glory (Psalm 19:1)
- Gather a people for Himself (1 Peter 2:9)
- Put His grace and justice on display through Christ (Romans 3:26)
- Bring all things under Christ (Ephesians 1:9-10)
Therefore the purpose of God with Scripture is to:
- Reveal Himself to us (Romans 1:20, Hebrews 1:1-2)
- Make us wise unto salvation (2 Timothy 3:15)
- Equip the people of God for every good work (2 Timothy 3:16-17)
- Guide, correct, and sanctify the church (Acts 17:11, John 17:17)
- Secure God’s covenant promises (Isaiah 40:8)
God is eternal and therefore His purposes are eternal.
The world is passing away, and also its lusts, but the one who does the will of God abides forever.
1 John 2:17 (LSB)
Discussion
The Bible is not a textbook on every subject. It is the revelation of God’s purpose to save a people for Himself. When you ask Scripture to do what it was never intended to do, you miss what it was intended to do. The sufficiency of Scripture is not a claim that the Bible answers every question. It is a claim that the Bible answers the questions that matter most.
Topic 3: No Additional Revelation
We do not need new prophecies, dreams, mysticism, or “words from God” to know how to live and what to believe. Scripture is complete. Nothing is to be added to it, and nothing is to be taken from it.
Of course, this teaching directly contradicts the teaching of Rome about the need for its oral traditions. It also contradicts the Charismatic fascination with new revelation. Be prepared for resistance from those who come from these religions.
Testing Against Scripture
The early church fathers were already facing fierce opposition from false teachers. They taught us not to wrestle with human philosophies and arguments, as the heretics do, but to use Scripture instead. Tertullian perfectly summed it up when he wrote:
Tertullian: “Take away, indeed, from the heretics the wisdom which they share with the heathen, and let them support their inquiries from the Scriptures alone: they will then be unable to keep their ground.”
Or, as Charles Spurgeon said:
Charles Spurgeon: “The Word of God is like a lion. You don’t have to defend a lion. All you have to do is let the lion loose, and the lion will defend itself.”
How Do We Come to an Understanding of Those Things That Are Not Plain?
Godly counsel, tradition, and spiritual experience are valuable, but they are never the final authority. The Bereans were commended because they “examined the Scriptures daily to see if these things were so” (Acts 17:11).
Now these were more noble-minded than those in Thessalonica, for they received the word with great eagerness, examining the Scriptures daily to see whether these things were so.
Acts 17:11 (LSB)
There are important reasons why we must examine Scripture. There have been many attempts to dilute or change the gospel to make it more attractive or to abuse the faith of believers. Therefore we must study Scripture to examine what we are being told, and we should also examine our own thoughts and convictions. Jesus even challenged people to examine Scripture on the claims that He made about Himself (John 5:39, 46; John 7:17; Luke 24:25-27).
According to the commentary on Acts by John MacArthur, there are four steps required to know God’s Word well enough to use it effectively:
- Confession of sin. 1 Peter 2:1-2 states that truth succinctly: “Therefore, putting aside all malice and all guile and hypocrisy and envy and all slander, like newborn babes, long for the pure milk of the word, that by it you may grow in respect to salvation.” It is impossible to study the Scriptures profitably with an impure mind.
- Bible study must be diligent. Paul commanded his beloved son in the faith, Timothy, to “be diligent to present yourself approved to God as a workman who does not need to be ashamed, handling accurately the word of truth” (2 Timothy 2:15). Lazy, haphazard, careless Bible study will not produce a Christian who is “mighty in the Scriptures” (Acts 18:24).
- Believers must be committed to practicing the truths they learn. James charged Christians to “prove yourselves doers of the word, and not merely hearers who delude themselves” (James 1:22). The ultimate goal of all Bible study is not increased knowledge but increased holiness and Christlikeness.
- Learn the truth by teaching others. We retain far more of what we study to teach others than of what we learn for our own benefit. The Old Testament believer Ezra is an example for Christians to follow. According to Ezra 7:10, he “set his heart to study the law of the Lord, and to practice it, and to teach His statutes and ordinances in Israel.”
The Sufficiency of Scripture Does Not Mean the End of Study
Some people hear “sufficient” and think it means “adequate” or “shallow.” The opposite is true. Because Scripture is sufficient, it is worth a lifetime of study. The Bereans examined the Scriptures daily. The doctrine of sufficiency does not make study unnecessary. It makes study worthwhile.
Discussion
When you hear a sermon or read a book, do you test it by Scripture? The Bereans did. They even tested the apostle Paul. If they tested an apostle, should we not test the teachers of our own day?
Topic 4: Our Responsibility
Every believer is called to good works (Ephesians 2:10), and Scripture is sufficient to equip us for those works.
For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand so that we would walk in them.
Ephesians 2:10 (LSB)
God created us after His image, exactly how He wanted us to be, and has planned good works for us as produced by our salvation and our walk with Him.
Scripture is our only source of learning who God is, why He saved us, what His plan for us is, and how we walk diligently with Him.
The second doctrine we studied said:
“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 ordinary means, may attain to a sufficient understanding of them.”
Engaging Roman Catholics
Start with common ground, not an attack. We share with Roman Catholics a belief that Scripture is the Word of God and a concern for societal issues. Begin there. Acknowledge their love for Christ and their desire for truth. This disarms defensiveness and opens the door for real conversation.
Focus on assurance, not just on authority. Roman Catholics do not have assurance of faith. The greatest gift we can give them is to tell them that salvation is free and of no cost to them. This is a powerful point of entry. Many devout Catholics are exhausted by the treadmill of sacraments, penance, and purgatory. You can ask: “Do you know, with certainty, that you are saved? Or do you live in fear of whether you have done enough?” The gospel offers the assurance they long for.
Use Acts 17:10-11 as your model. The Bereans “received the word with all eagerness, examining the Scriptures daily to see if these things were so.” They tested even apostolic teaching against the written Word. This is a gentle way to introduce the principle of Sola Scriptura: even Paul’s teaching was tested by Scripture. If the Bereans tested an apostle, should we not test the traditions of men?
Be prepared to discuss Sola Scriptura directly. It is guaranteed that this issue will come up. The key question is: Where does the final authority lie? Is it in Scripture alone, or in Scripture plus tradition plus the Magisterium? A helpful question: “If the Pope and the Bible disagreed, which would be the final authority for you?” This gets to the heart of the issue without being needlessly confrontational.
Avoid Chick tracts and antagonism. Avoid material that portrays Catholics in a derogatory manner. This closes doors immediately. Speak the truth in love (Ephesians 4:15).
Key Scripture for Roman Catholics:
- Acts 17:10-11 — The Bereans tested apostolic teaching against Scripture.
- Mark 7:13 — “You nullify the word of God by your tradition.”
- Isaiah 8:20 — “To the law and to the testimony! If they do not speak according to this word, they have no light of dawn.”
Engaging Charismatics
The key issue with Charismatics is usually not whether they believe Scripture, but whether they treat it as the final authority.
Distinguish between the gift and the revelation. The biblical purpose of the sign gifts was “special authenticating and revelatory functions in the first century only.” Once the canon was complete, the “partial” revelation ceased. You can ask: “If God is still giving new revelation today, how do we know which prophecies are true and which are false? How do we test them?”
Use the test of Scripture itself. Deuteronomy 18:20-22 gives a clear test: if a prophet speaks in the name of the Lord and the thing does not happen, that prophet is false. Ask your Charismatic friend: “Have you ever heard a prophecy that did not come true? What did you do with it?” This can gently open their eyes to the practical problems with ongoing revelation.
Point to the sufficiency of Scripture. Many Charismatics “affirm Grudem’s theology of a low level of authority for their experience, while consistently emulating the practices of a ‘higher-level’ experience.” In other words, they say prophecy is subordinate to Scripture, but in practice, they treat it as equally authoritative. You can gently point out this inconsistency: “You say Scripture is your final authority, but when someone gives a ‘word from the Lord,’ do you test it by Scripture, or do you feel obligated to obey it?”
Acknowledge the real desire behind it. Many Charismatics pursue spiritual experiences because they long for intimacy with God. The uniqueness of Scripture is often sacrificed in the pursuit of “something new and esoteric.” You can affirm their hunger for God while pointing them to the sufficient provision He has already given in His Word.
Key Scripture for Charismatics:
- Hebrews 1:1-2 — God has spoken definitively in His Son.
- Jude 3 — The faith was “once for all delivered to the saints.”
- 2 Timothy 3:16-17 — Scripture equips us for every good work.
- Revelation 22:18-19 — A severe warning against adding to God’s Word.
Discussion
When you share the sufficiency of Scripture, be prepared for resistance. Roman Catholics will appeal to tradition and the Magisterium. Charismatics will appeal to dreams, visions, and prophetic words. These are not merely academic disagreements. They are matters of authority. Engage with love. Ask questions. Do not seek to win an argument, but to help them see that their own stated beliefs, if taken seriously, point back to Scripture.
Pastoral Note
When you face a decision, you do not need to search for a secret word from God. You need to search the Scriptures. They are sufficient to guide you. When you face a struggle, you do not need to rely on human wisdom alone. The Word of God is sufficient to speak into your struggle. When you are counseling a brother or sister, you do not need to be an expert in psychology. You need to be faithful with the Word of God. It is sufficient for soul care.
The sufficiency of Scripture means that God has not left us without a guide. He has given us His Word — complete, sufficient, and sufficient for every need. We do not need to look elsewhere. We need to open the Book.
So faith comes from hearing, and hearing by the word of Christ.
Romans 10:17 (LSB)
Further Study For deeper study of this doctrine, the following commentaries are freely available online and are worth consulting:
- For devotional reading and practical application: Matthew Henry (Concise) — warm, pastoral, and suitable for all readers.
- For balanced scholarship and lay-friendly depth: Jamieson, Fausset, and Brown (JFB) — scholarly but not overly technical.
- For advanced exegetical study: John Calvin — precise and foundational, but demanding.