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In this episode of The Reformed Standard, we explore Westminster Shorter Catechism Question 3: “What do the Scriptures principally teach?” The answer provides a profound organizational framework for the entire Christian life: “The Scriptures principally teach what man is to believe concerning God, and what duty God requires of man.” This episode unpacks how Scripture’s structure follows a vital pattern of indicative (what is true) before imperative (what to do), reflecting the grace-based nature of our relationship with God. Just as adoption legally establishes a child’s identity before family rules are taught, so too does God establish our identity in Christ before calling us to obedience. This ordering—belief before duty—is not arbitrary but forms the very grammar of the gospel, revealing that we obey not to earn God’s favor but because we already have it through Christ.
Key Takeaways
- The Scriptures can be understood through two great categories: belief (doctrine) and duty (life), with belief necessarily preceding duty
- The “indicative-imperative” pattern (what is true before what to do) is woven throughout Scripture and forms the foundational grammar of the gospel
- Christians are called to act from their secure position as God’s children, not to earn that status
- Ephesians 2:8-10 perfectly demonstrates this pattern—we are saved by grace through faith (indicative), then called to good works (imperative)
- Even the Ten Commandments begin with a declaration of grace (“I am the LORD your God, who brought you out of Egypt”) before any commands are given
- The Christian life centers around a singular duty—loving God and neighbor—rather than an overwhelming checklist of religious tasks
- Our obedience is the joyful response of children who already have God’s favor, not a frantic effort to earn it
Key Concepts
The Indicative-Imperative Order in Scripture
Throughout Scripture, we see a consistent pattern where God establishes who we are before He tells us what to do. This pattern is particularly evident in Paul’s epistles, which typically begin with extensive theological foundations (indicatives) before transitioning to practical applications (imperatives). Romans exemplifies this structure with eleven chapters of doctrine before the pivotal “therefore” of Romans 12:1 introduces the practical section. This order isn’t merely stylistic—it reflects the very nature of God’s relationship with His people. God acts in grace first, establishing our identity as His children through Christ’s finished work, and only then calls us to live in accordance with that new identity. Reversing this order leads to legalism, where we attempt to earn a status that can only be received as a gift.
The Christian’s Singular Duty
The catechism specifically uses the singular term “duty” rather than “duties,” revealing a profound truth about the Christian life. While Scripture contains many commands, they all flow from and point back to a singular orientation of the heart toward God. Jesus summarized this unified duty in the two great commandments: love God with all your heart, soul, mind, and strength, and love your neighbor as yourself. This singularity of purpose liberates believers from the crushing burden of legalistic box-checking and reorients our entire existence toward pleasing the One who has already accepted us. The Christian life isn’t about frantically trying to fulfill an endless list of obligations but about a wholehearted devotion to God that expresses itself in various forms of obedience, all flowing from a heart transformed by grace.
Memorable Quotes
“We act not to obtain a status or a reward from God, but because we already have it in Christ. We seek to live like sons of the King because, by grace, that is what we are.”
“Our duty is not a frantic effort to earn God’s favor; it is the joyful response of a child who already has it.”
Full Transcript
Last time, we stood before the vast library of Scripture and wrestled with a very real and honest question: with so much here, where do we even begin? We ended by asking the catechism’s third question: What do the Scriptures principally teach? We left that question to meditate on, to consider how this one, unified book directs us toward our chief end of glorifying and enjoying God.
[00:00:30] The Catechism’s Answer: Belief and Duty
Today, we turn to the catechism’s beautifully simple, yet profoundly deep, answer. The answer that provides the organizing principle for the entire Christian life.
The scriptures principally teach what man is to believe concerning God, and what duty God requires of man.
This answer is a gift of immense clarity. It’s the legend for the biblical blueprint. It tells us that everything we read in the sixty-six books of the Bible can be understood through these two great categories: belief and duty. Doctrine and life. The indicative and the imperative. And the order is not accidental.
Let’s take this answer in two parts, just as it’s presented.
[00:01:11] The Foundation of Belief
First, the Scriptures teach us what we are to believe concerning God. This is the foundation. In the letters of the Apostle Paul, we see this pattern repeated over and over. He begins with theology—the indicative. He lays out what is true about God, about Christ’s work, and about who we are now because of that work. Only after laying that solid doctrinal foundation does he move to the commands—the imperative. He tells us what is true before he tells us what to do.
[00:01:41] The Grammar of the Gospel
This sequence is the very grammar of the gospel. God, in His mercy, claims His people and makes them His own before He commands them. It is from this secure position—this identity as His chosen children—that we are called to act. We act not to obtain a status or a reward from God, but because we already have it in Christ. We seek to live like sons of the King because, by grace, that is what we are. If we get this order wrong, we condemn ourselves to a life of perpetually trying to earn God’s favor, a burden we can never bear and were never meant to.
Think of it this way. Imagine a child adopted into a new family. The legal decree of adoption—the unchangeable reality that makes him a son—is the indicative. It’s a fact, a gift of grace he did not earn and cannot lose. From that moment forward, he begins to learn the family’s ways. He is taught how to live, how to act, how to honor his new father. That is the imperative. His obedience doesn’t earn his sonship; it flows from his sonship. He acts like a son because he is a son. This is precisely how the gospel works in our lives.
[00:02:49] The Indicative and the Imperative in Paul’s Letters
Paul makes this crystal clear in his letter to the Ephesians, chapter two. I want to focus on just three verses there, verses 8 through 10, which perfectly summarize this entire dynamic. Paul writes: “For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast.”
Notice the absolute exclusion of our efforts. Paul is meticulous here. He says salvation is by grace, through faith. And then, just to be sure we understand, he says “this is not your own doing.” He’s referring to the entire process. The fact that salvation is even possible by grace through faith is itself the gift. One cannot boast in a gift they received; that would be nonsense. Paul shuts every door to human pride. That is the indicative. That is what we are to believe.
But he doesn’t stop there. He immediately moves to the purpose for which we were saved. Verse 10: “For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand, that we should walk in them.”
Here is the transition to duty.
We are saved for good works, not by them. We are God’s “workmanship,” His masterpiece. And just as a great work of art brings glory to the artist who created it, so our lives, lived out in the good works God has prepared for us, are meant to bring glory to Him. Our new identity in Christ comes with a new purpose.
And this pattern, this grammar of grace, isn’t just something Paul came up with. It is woven into the very fabric of God’s self-revelation, going all the way back to the foundation of Israel’s moral life.
[00:04:31] The Ten Commandments: Grace Before Law
Think about the Ten Commandments. How do they begin? Do they start with “You shall not…”? No. They begin with a declaration of grace. The very first thing God says from Sinai in Exodus 20 is the great indicative: “I am the LORD your God, who brought you out of the land of Egypt, out of the house of slavery.”
Before a single command is given, God reminds His people of who He is and what He has done for them. He is their Redeemer. He has already rescued them. Their identity as a saved people is established first. Only after that powerful declaration of His covenant love and saving action does He then give them the law. The commands are not a ladder for them to climb out of slavery; they are the family rules for the people who have already been brought into the freedom of God’s house. Obedience is not the cause of their redemption; it is the consequence of it.
We see this grand structure not just at Sinai, but across the New Testament.
[00:05:33] Romans: Doctrine Before Duty
The book of Romans is perhaps the clearest example. For eleven straight chapters, Paul lays out the most comprehensive, soaring, and profound doctrine in all of Scripture. He details our sin, God’s righteousness, justification by faith, the work of the Spirit, the security of the believer, and God’s sovereign plan for history. It is a monumental indicative.
And after all of that, how does he begin his section on practical application? With one of the most famous pivots in the Bible, in chapter 12, verse 1: “Therefore, I urge you, brothers and sisters, in view of God’s mercy, to offer your bodies as a living sacrifice…” Notice that. All our duty, all our sacrifice, all our obedience is offered ‘in view of God’s mercy.’ The imperative is the direct, logical, necessary response to the indicative that came before it.
And that brings us to the second half of the catechism’s answer, and to a single word that is full of profound significance.
[00:06:32] The Singular Duty of the Christian Life
The Scriptures teach what duty God requires of man. Notice, it doesn’t say “what duties,” plural, as if the Christian life is an endless checklist of religious tasks. It says “what duty,” singular.
This is intentional and deeply pastoral. The Christian life is not about frantically trying to keep up with an infinite multiplicity of laws. It is about a singular orientation of the heart, a “true north.” Our ultimate duty, the one duty that encompasses all others, is to serve, worship, and obey the God who has created us and, in Christ, redeemed us. This one duty takes many forms, but it is graciously summarized for us by Christ Himself in the two great commandments: to love the Lord your God with all your heart, soul, mind, and strength; and to love your neighbor as yourself.
Though there are many laws in Scripture, there is one Law, and it is the Law of love for God and neighbor. Understanding our duty as a singular call to love and obey God protects us from the legalistic burden of box-checking. It reorients our entire life toward a single goal: living in a way that pleases the one who has already accepted us as His children.
[00:07:45] Conclusion and Summary
So, this is what the Scriptures principally teach. First, the indicative: the glorious truth of who God is and what He has done for us in Christ. And then, flowing directly from that truth, the imperative: the singular duty to live a life of loving obedience in response to His grace.
Our duty is not a frantic effort to earn God’s favor; it is the joyful response of a child who already has it.