Chapter 5 begins the pivot from diagnosis to remedy by redefining repentance. Keller posits that the core problem for both the rebellious and the moralistic is Sin as Self-Salvation—living, in practice if not in word, as though God were unnecessary. True repentance, therefore, means reckoning with the pride that underpins this spiritual attitude. Though Keller does not say so explicitly, the problem is that human nature, as understood in Christian theology, makes this reckoning impossible; as a result of the Fall, humanity inclines inevitably toward sin. This idea is particularly dominant in the Calvinist tradition out of which Presbyterianism arose, where it is sometimes called the doctrine of “total depravity.” For repentance to occur, God must therefore intervene preemptively. God’s initiating love is thus the cause, not the effect, of repentance, a concept that subverts the logic of merit-based religion by establishing grace as a proactive force.

Keller suggests that the specific nature of this remedy is revealed through a deliberate omission in the parable that emerges via juxtaposition: Unlike the stories of the Lost Sheep and Lost Coin, no one actively searches for the lost son, creating a narrative vacuum that implies the need for a “true elder brother” to rescue his sibling. Further, Keller argues, that figure must bear the “cost” of forgiveness, thus explicitly introducing the theme of Costly Grace and the True Elder Brother. Using an economic metaphor, the text argues that grace is not the cancellation of a debt but its transfer; mercy does not override justice but satisfies it through substitution, establishing the need for a savior. Keller then resolves the parable’s tensions by presenting Jesus as the “true elder brother” who fulfills this missing role. 

This section, then, is the most explicit example yet of Keller’s Christocentric approach to exegesis. Adopted from theologian Edmund P. Clowney, this interpretive lens posits that every biblical text must be understood within the Bible’s larger salvation narrative. As Clowney argues, “To see the text in relation to Christ is to see it in its larger context, the context of God’s purpose in revelation” (Clowney, Edmund P. Preaching Christ in All of Scripture. Crossway, 2003, p. 12). This approach is likewise evident not only in Keller’s interpretation of the Cain and Abel story—a tale in which a brother fails even more dramatically in his obligations—but in the way he ties the Genesis story to the Parable of the Prodigal Son. For Keller, the stories are thematically linked in ways that go deeper than Jesus’s presumed familiarity with the Old Testament. Rather, they establish a pattern that Jesus himself fulfills and can therefore only be understood holistically. 

To emphasize this point, Keller draws attention to various narrative parallels between the Parable of the Prodigal Son and the story of Jesus’s life: 

Think of the kind of brother we need. We need one who does not just go to the next country to find us but who will come all the way from heaven to earth. We need one who is willing to pay not just a finite amount of money, but, at the infinite cost of his own life to bring us into God’s family, for our debt is so much greater (94-95). 

Though Keller does not extrapolate on these similarities, the passage treats the parable as an allegory for sin and salvation not merely on the individual level but on the level of humanity as a whole. 

To illustrate this theology’s spiritual impact, the analysis draws on cultural analogies and historical hymns. Examples from the film Three Seasons and the works of John Newton and William Cowper show how apprehending Jesus’s costly, selfless love transforms the individual’s relationship to God, reordering their affections and turning “duty into choice” (100).