The Prodigal God: Recovering the Heart of the Christian Faith

In The Prodigal God, Keller sets out to clarify the Christian conception of sin by tracing it to any attempt to create worth or security without God. Keller roots this argument in the Parable of the Prodigal Son, where sin emerges as a project of self-salvation. The younger brother chooses open defiance, while the elder brother clings to strict moral effort, yet each son pursues independence from God. Keller therefore argues that genuine repentance must grapple with the desire to justify oneself, not only with visible wrongdoing.

In contrasting the two brothers, Keller identifies two basic ways in which humans try to achieve happiness. The first is self-discovery, which often manifests as a rejection of social norms. Thus, the younger brother concludes that he does not need to obey his father, work hard, or participate in his broader community to lead a fulfilling life. He substitutes his own moral code for society’s, which, by analogy, is also God’s. The second approach to life involves moral conformity, but the elder brother’s story shows how obedience, too, can become a disguised form of revolt. The elder son keeps every rule and praises his own record, yet his goal is to place his father in his debt. When he describes years of “slaving” for his father, he makes it clear that he expects control over the family’s resources and over decisions about forgiveness. This implies that he also believes he knows what is best for himself and has simply chosen a different means of attaining it: The elder brother tries to manage his father (God) through good behavior rather than trust in his grace. Keller therefore argues that any action or mindset that elevates one’s own wishes and goals over God’s, however covertly, is both sinful and futile because “You are serving as your own Savior” (44). 

Keller’s analysis of Salieri in Amadeus highlights some of the signs one is engaged in this kind of rebellion. Anger is particularly telling: Because Salieri’s “virtue” is a bargain for glory, not an expression of love, it collapses into rage when Mozart receives the gift Salieri wanted. Keller links this collapse to the elder brother’s fury when the father’s mercy disrupts his expectations. Salieri’s simultaneous jealousy of and disdain for Mozart similarly resonate with Keller’s list of “elder brother” traits, as they imply a sense of both insecurity and superiority. Someone who has truly absorbed the Christian message, Keller argues, recognizes their own sinfulness while also understanding that God loves them regardless; they therefore do not need to prove anything in their interactions with others. 

Because Keller defines sin as a refusal to trust God’s rescue, he argues that repentance must reach beyond specific wrongs to encompass the basic human stance toward God, which Christianity teaches has been one of rebellion ever since the Fall. He writes that a Christian must “repent of the reasons [they] ever did anything right” (87). This approach brings hidden motives to the surface since rule-breaking and rule-keeping can each protect a sense of self-sufficiency. Only by confessing the urge to build worth without God can a person understand the gospel and accept God’s grace.