Profile PictureMUSTARD SEED DISCIPLESHIP by McKay Caston

The Beauty of Sanctifying Grace: Fruitfulness is Not a Duty as Much as It is a Gift

NOTE: This is a sample lesson in the Mustard Seed devotional study course Facets of Grace: Seeing and Savoring the Beauty of God's Grace in Jesus. If you're interested in the course for personal use or in a small group, for your family, church staff, etc., just click the button below. 🙂

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A couple of lessons back, I cited the Westminster Shorter Catechism’s pithy definition of justification as “an act of God’s free grace” that forgives sin and imputes righteousness to the believer. The distinctive word in that definition is “act,” where God declares something.

The Westminster Shorter Catechism’s definition of sanctification is just as succinct with one word change that reveals the primary distinction between the two important doctrines. Here is how the answer to WSC question number 35 reads. See if you can detect the change.

Sanctification is the work of God’s free grace, whereby we are renewed in the whole man after the image of God, and are enabled more and more to die unto sin, and live unto righteousness.

Did you catch it? Justification is the act of God’s free grace, while sanctification is a work of God’s free grace. What is the difference? 1

  • First, in the act of justification, we are passive recipients of a one-time declaration. In the work of sanctification, we are active participants in an ongoing process.
  • Second, the act of justification is God’s redemptive work for me, while the work of sanctification is God’s redemptive work in me.
  • Third, the act of justification is a static, legal declaration where I’m given a new positional status. The work of sanctification is a dynamic, personal transformation where I’m giving a new spiritual and moral ability.

The concept of “spiritual and moral ability” gets to the heart of sanctification. You may have noticed the Catechism definition of sanctification uses the word “enabled” to describe the work of the Spirit in the believer. This is the core of spiritual change—being supernaturally empowered to live like Jesus as someone being “renewed” in the image of Christ.

  • We are empowered to love like Jesus.
  • We are empowered to forgive like Jesus.
  • We are empowered to endure trial and suffering like Jesus.

Sanctification teaches us that justified believers, being indwelt by the presence and power of the Holy Spirit through union with Christ, can face spiritual and moral challenges with the same power that raised Jesus from the dead. Paul says as much in Romans 6:4, writing,

We were therefore buried with (Christ) through baptism into death in order that, just as Christ was raised from the dead through the glory of the Father, we too may live a new life.

By the way, living a new life is not a duty we must fulfill. Sanctifying, enabling grace to live by the wisdom of God is a gift. After all, sin isn’t only wrong, it is harmful. Holiness isn’t only right, it is the path of human flourishing.

But we know that sin lurks within each of us and remains a powerful force, even in the life of a believer. How can we face the continual barrage of challenges, temptations, and obstacles?

Moving the Tree

Consider an illustration. You are driving down a single-lane dirt road in a forest lined with massive trees. As you drive, heavy winds blow down a huge two-hundred-year-old oak across the road. You cannot go over the tree or around it. And you can’t turn around, as there are no shoulders on the dirt path.2

Using this analogy, the tree represents any challenge, temptation, or problem we face. As I approach the obstacle, I have four options.

Option 1

I can sit and wait for the Lord to move it for me. This is the let go and let God approach to sanctification, where I play no part in the process. This is not the way he has designed the tree to be moved.

So we move to option 2.

Option 2

I can try to move the tree myself with the classic willpower approach. I think we’d be surprised how many of us choose this option, which of all courses of action is the most arrogant (as if I could move a several-ton tree by myself) and the most futile.

So, we move to option 3.

Option 3

I can try to pick up one end of the tree, expecting the Lord to pick up the other end. This is the God and me approach to sanctification, where God helps supply what is lacking in my strength. The problem is, I am too weak to lift even one side.

So, in desperation, we move to the fourth and final option.

Option 4

I confess my total weakness and inability to move the tree and ask Jesus to do something miraculous, which is to fill me with his Spirit, who can move the tree out of the way with my hands but in his power.

This is how sanctification works. We are active participants. Our hands are on the tree. But it is the Spirit within who enables the tree to move.

If justification is God’s work for me through the sacrifice of Jesus, sanctification is God’s work in and through me by the presence and power of the Holy Spirit.

Dynamics of Personal Change

This understanding of God’s work for me and God’s work in and through me corresponds with Jesus’ teaching on the relationship between justification and sanctification in John 15, where he speaks of himself as a vine and his disciples as branches.

4 Abide in me, and I will abide in you. As the branch cannot bear fruit by itself, unless it abides in the vine, neither can you, unless you abide in me. 5 I am the vine; you are the branches. Whoever abides in me and I will abide in him and he will bear much fruit, for apart from me, you can do nothing.

The metaphor of a vine and branches is a uniquely helpful word picture for the Christian life. If my initial engraftment into the Vine represents justification, the fruit that grows on the Vine represents sanctification. 3

But how does fruit grow? Does the branch strain to produce a cluster of grapes? No, as the branch presses into the vine, sap flows from the vine into the branch with the substance that will become fruit.

You Can Change (But Not by Trying Harder)

What do you want to change in your life? I want to be humble, repentant, and teachable in the face of criticism. But my flesh typically responds to criticism with defensiveness and counterattacks. True disciples of Jesus want to honor him with practical devotion by walking in his ways according to his wisdom.

Yet Paul would lament in Romans 7:18b-21 how holy desire often succumbs to unholy action.

For I have the desire to do what is good, but I cannot carry it out. 19 For what I do is not the good I want to do; no, the evil I do not want to do—this I keep on doing. 20 Now if I do what I do not want to do, it is no longer I who do it, but it is sin living in me that does it. 21 So I find this law at work: When I want to do good, evil is right there with me.

The good news of justification is, to be forgiven, you don’t have to change. You know the hymn, “Just as I am, without one plea, by that Thy blood was shed for me.” God saves us by grace alone.

The good news of sanctification is, once forgiven and reconciled to God by grace, you can change and will want to change—not to be saved, but because you already are.

The bad news is, you can’t change yourself. Remember, we are not only saved by grace; we are changed by grace. As Jesus said, apart from his enabling grace, you can do nothing—not by trying harder, not by making promises, not by doing penance. Nothing.

We can summarize the dynamic of spiritual change with three brief points.

  1. I cannot change myself.
  2. Jesus can change me.
  3. My job is to abide in him as my perfect righteousness, letting the sap of the Holy Spirit fill me and change me by grace. 4

The Primary Effort

This means that the primary effort in the Christian life is not the pursuit of moral change. The primary effort is to abide in the perfect moral record of Jesus as my own. Then, and only then, is real, deep, lasting change possible. Only when I am confident that I am safe will I be free to confess my weakness, own my sin, and submit to walking in the ways of the Lord as the way to experience maximum blessing in this life.5

Remember, sanctification is not a duty. It is a gift.

The protestant reformer, John Calvin, once said, “Those whom the Father justifies, he sanctifies.” That is the place we must start. The primary question is not am I being sanctified, but have I been justified by the blood of Jesus? Do I believe my sins has been nailed to the cross and I bear them no more?

If you have believed that, rest there. Marinate in the mercies. As your soul learns to rest in God’s justifying grace, you will be filled with the empowering grace of the Holy Spirit, who can do in you immeasurably more in and through you than you could ever ask or imagine — all to the praise of God’s glory.

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Discussion Questions

  1. Which of the four sanctification "options" tends to be your default?
  2. What does the image of the Vine and the branches teach us about the organic dynamic of personal change?
  3. What is the primary "effort" of the Christian life? Why is this surprising? Why is it not surprising?
  4. How is sanctification a facet of grace?


1 It is critical that we understand these distinctions, lest we (even if unintentionally) make sanctification a shifting foundation of our justification instead of our justification the absolute ground for our sanctification.

2 I first heard a version of this analogy from my friend, Les Newsom.

3 In Galatians 5, Paul describes what he calls “the fruit of the Spirit.” You know them: love, joy, peace, patience, kindness, goodness, gentleness, self-control, etc. When Jesus speaks of fruit using the metaphor of the vine and branches, he envisions the same kinds of produce.

4 What takes place next is truly supernatural as the Spirit begins to rewire the heart with new desires, changing your life motivation from serving self to honoring the Savior.

5 Like anyone who has been through AA knows, the first step to change (recovery) is confessing helplessness. In ourselves, we are helpless. Victory over both the penalty and power of sin is found in Jesus.


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