A sermon preached at Covenant Presbyterian Church of Fort Smith, Arkansas on April 26, 2026.
And he said to his disciples, “Temptations to sin are sure to come, but woe to the one through whom they come! It would be better for him if a millstone were hung around his neck and he were cast into the sea than that he should cause one of these little ones to sin. Pay attention to yourselves! If your brother sins, rebuke him, and if he repents, forgive him, and if he sins against you seven times in the day, and turns to you seven times, saying, ‘I repent,’ you must forgive him.” The apostles said to the Lord, “Increase our faith!” And the Lord said, “If you had faith like a grain of mustard seed, you could say to this mulberry tree, ‘Be uprooted and planted in the sea,’ and it would obey you” (Luke 17:1–6).[1]
Throughout the last chapter, Jesus was not only teaching the crowds at large but confronting the Pharisees specifically. And while they are not far from his mind, he now turns from addressing his hardened adversaries to his disciples, those learning how grace reshapes life individually and collectively. I use the word grace here because what Jesus is teaching us about forgiveness can seem impossible, especially for those who have been wounded by others in the church. What Christian would disagree that repentance and forgiveness are core characteristics of the Christian faith? And yet, sometimes harboring resentment can seem like righteous justice, not forgiving can feel like a judgment pronounced, holding on to how someone hurt you can seem like a logical defense. But the grace of God confronts such notions not with judgment and shame but sacrificial love: “For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God” (2 Cor. 5:21). Such righteousness we have received by God’s grace through faith in Christ alone, and by this same grace through faith we too may bestow the grace of forgiveness.
Beware Stumbling Blocks
Jesus begins with a sober warning: “Temptations are sure to come” (Luke 17:1a). In the Greek, the word translated “temptations” here is literally “stumbling blocks,” used figuratively to mean those things over which people fall into sin. And not one of us is immune to falling. While we are born again to new life in Christ and justified as righteous before God through faith, while we are adopted into God’s family and sanctified by the indwelling presence of his Spirit, we are not yet freed from our sinful flesh.
On the one hand, the Apostle Paul explains, “We know that our old self was crucified with [Christ] in order that the body of sin might be brought to nothing, so that we would no longer be enslaved to sin” (Rom. 6:6). On the other hand, we know how Paul feels when he confesses,
For I do not understand my own actions. For I do not do what I want, but I do the very thing I hate. . . . For I delight in the law of God, in my inner being, but I see in my members another law waging war against the law of my mind and making me captive to the law of sin that dwells in my members (7:15, 22-23).
In what sounds like a contradiction of exclamation, Paul cries out, “Wretched man that I am! Who will deliver me from this body of death? Thanks be to God through Jesus Christ our Lord!” (7:24-25a). Except, it’s not a contradiction: In Christ we have truly been saved from sin, and daily we wage war against sin. We are then, every one of us, susceptible to temptations. Danger comes when we think that we are not.
It stands to reason then that we would pray daily as our Lord Jesus taught us to pray, “And lead us not into temptation, but deliver us from evil” (Matt. 6:13). In praying this, we are in essence asking our heavenly Father to spare us from circumstances that would tempt us to sin. And sadly, this includes those through whom temptations come.
Jesus states this warning with a woe: “woe to the one through whom they come!” (Luke 17:1b). And it is here that I think “stumbling blocks” is a more appropriate translation, because there are those who not only sin but cause others to stumble over and into it. The issue is not only that stumbling blocks exist, but that they can come through people. Given his recent conflict with and condemnation of the Pharisees, contextually we may assume he is alluding to them. It’s a fair assumption, since elsewhere Jesus cautioned, “Let them alone; they are blind guides. And if the blind lead the blind, both will fall into a pit” (Matt. 15:14). Blind guides have no business leading, and woe to the one who follows.
Let us likewise heed his warning that we be not led astray and that we not lead others with us. It is one thing to sin but another to lead a fellow “little one” to sin: to entice a weaker brother, to lead a child astray, to normalize what God forbids, to model a careless Christianity. It should not surprise then that Jesus says, “It would be better for him if a millstone were hung around his neck and he were cast into the sea than that he should cause one of these little ones to sin” (17:2). A millstone is a heavy stone used for grinding grain into flour not to be worn for swimming laps. A millstone around one’s neck guarantees certain death by drowning. And this would be better, Jesus says, than leading a brother or sister to sin.
Pay Attention to Yourselves
Jesus expresses this sentiment then with this imperative: “Pay attention to yourselves!” (17:3a). Sin is selfish. It blinds us not only to conformity to God’s law but also to the needs of our neighbor. The effects of sin are not purely personal but relational too. Therefore, Jesus gives us this practical direction: “If your brother sins, rebuke him, and if he repents, forgive him, and if he sins against you seven times in the day, and turns to you seven times, saying, ‘I repent,’ you must forgive him” (Luke 17:3-4). If we sin, what then? Shall we hide it? Dismiss it? Embrace it? Jesus says, first, rebuke it, which requires both courage and love. To be clear, Jesus is not calling us to be faultfinders, busily pointing out one another’s sin. Rather, he is warning us against indifference to sin. Christian love does not ignore what destroys; it confronts it.
In a culture that prizes tolerance above truth, this command feels jarring. Yet Scripture is clear: sin concealed is sin unhealed. As Proverbs 28:13 teaches, “Whoever conceals his transgressions will not prosper, but he who confesses and forsakes them will obtain mercy.” To rebuke, then, is not to condemn, but to care. It is an act of spiritual responsibility within the body of Christ.
The objective of such love is repentance and restoration. If rebuking requires courage, repentance requires humility. When you and I are confronted with our sin, our instinct is often to defend, minimize, or deflect. But God’s grace trains us otherwise. After all, it is God’s kindness that leads us to repentance.[2] Repentance is not regretting what we have done but turning from it. It is calling sin “sin” without excuse and forsaking it without delay. As the Westminster Shorter Catechism explains, “Repentance unto life is a saving grace, whereby a sinner, out of a true sense of his sin, and apprehension of the mercy of God in Christ, doth, with grief and hatred of his sin, turn from it unto God, with full purpose of, and endeavor after, new obedience.”[3] For this reason, James exhorts, “Confess your sins to one another and pray for one another, that you may be healed” (James 5:16). There is healing, real spiritual restoration, that accompanies true repentance.
And, as it is God’s kindness that leads us to repentance, so we are to forgive one another graciously. Jesus makes this unmistakably clear: “If he repents, forgive him” (Luke 17:3), not once only but repeatedly, “seven times in the day” (17:4). Of course, Jesus isn’t teaching us arithmetic but ethos. He’s describing a heart shaped not by law but grace, a heart that doesn’t keep score. We are to be quick to forgive our brothers and sisters, not reluctantly, not conditionally, but freely. Why? Because forgiveness is not rooted in the worthiness of the offender, but in the grace of God toward us. The forgiven become forgivers.
In this way, the church becomes a community of grace, where sin is neither ignored nor excused, where repentance is neither delayed nor superficial, and where forgiveness is neither withheld nor measured. And James reminds us of the stakes: “Whoever brings back a sinner from his wandering will save his soul from death and will cover a multitude of sins” (Jas. 5:19-20). Paying attention to ourselves then is not isolated introspection but mutual care under the rule of grace.
Believe the Impossible
Perhaps considering Jesus’s command too hard, even impossible to obey, his apostles make a noble request: “Increase our faith!”Truly, the kind of forgiveness Jesus demands is naturally impossible. But Jesus’s answer is both surprising and corrective: “If you had faith like a grain of mustard seed, you could say to this mulberry tree, ‘Be uprooted and planted in the sea,’ and it would obey you” (17:6).In other words, the issue is not the quantity of faith but its presence.Even the smallest true faith is powerful enough to enable us to obey the Lord.
The image of uprooting a mulberry tree, a tree known for deep roots, naturally depicts what seems impossible.And what is more deeply rooted than resentment? What is more entrenched than wounded pride, long memory, or quiet bitterness?What is harder to uproot than a perpetually held grudge? Yet by faith, even these can be uprooted.
How? Not by willpower, not by greater degrees of faith, but by looking to Christ, the object of our faith.For the grace we are commanded to show is the grace we have first received. We forgive because we have been forgiven. We release others because God in Christ has released us from an unpayable debt.At the cross of Christ, divine justice and mercy met, where sin was neither ignored nor excused but atoned for. And from that fountain flows the grace that enables us to forgive others, not minimally, not conditionally, but truly and abundantly.
The grace of forgiveness is not natural but supernatural. It requires vigilance against causing others to stumble. It demands honest self-examination and courageous engagement with sin. And it calls for a faith that rests not in itself, but in the God who forgives sinners. For some it may sound like an impossibility, but as Jesus explained elsewhere to his disciples, “with God all things are possible” (Matt. 19:26).
So, the question is not “Can I forgive?” but “Do I believe the gospel?” Do I believe that God has shown mercy to me? Do I believe that God has bestowed his grace upon me? It’s a matter of faith. And by this very same faith, we too can show mercy, bestow grace, forgiving as we have been forgiven. Such is the grace of forgiveness.
[1] Unless referenced otherwise, all Scripture quotations are from The Holy Bible, English Standard Version
(Wheaton: Crossway Bibles, 2001).
[2] Rom. 2:4
[3] Q. 87, https://opc.org/sc.html
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