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At a glance
Sin is often reduced to a list of forbidden individual acts — things you do wrong — which can make the doctrine feel arbitrary, moralistic, or beside the point for people who "keep the rules" reasonably well.
Sin is more deeply a disordered love — building your identity and meaning on something other than God — that distorts your relationship to yourself, others, and creation, whatever that something is.
Relevant Scripture
“The heart is deceitful above all things, and desperately wicked: who can know it?”
Jeremiah 17:9 KJV
UECF.NET summary
Keller opens Part Two's constructive theology by redefining sin away from a simple checklist of forbidden acts. Drawing on Augustine's image of being "curved in on oneself," he describes sin fundamentally as a disordered love: making something other than God — career, romance, family, morality, political cause, even religion itself — the ultimate source of identity, worth, and meaning. Anything besides God pressed into that role becomes an idol, and idols reliably fail to bear the weight only God can bear.
This reframing explains why sin distorts more than isolated behavior. If your worth depends on career success, failure becomes unbearable and success breeds contempt for those who haven't achieved it. If your identity rests on being a good, moral person, moral failure in yourself or people close to you becomes intolerable, and you grow harsh and judgmental toward others. If a relationship becomes the ultimate source of meaning, ordinary human limitations in the other person become existential threats. Keller's point is that sin, understood this way, is not merely isolated rule-breaking that a good record can offset, but a deep orientation of the heart that shapes everything — anxiety, cruelty, and emptiness all trace back to asking a created thing to be what only the Creator can be. This chapter sets up chapter 11's central distinction between religion (moral performance to earn worth) and the gospel (worth received as a gift), since both moralism and immorality, in Keller's account, are different strategies for the same underlying sin of self-salvation.
Main themes
- Sin as disordered love and misplaced identity, not merely as isolated rule-breaking.
- Idolatry: making a good created thing carry the ultimate weight only God can bear.
- Both moral failure and moral "success" can spring from the same underlying self-centered orientation.
- This deeper diagnosis of sin sets up the religion-versus-gospel distinction in the next chapter.
Key ideas
- Augustine's "incurvatus in se" (curved in on oneself) pictures sin as a bent orientation, not just discrete acts.
- Idols are typically good things (family, achievement, morality) turned into ultimate things.
- Building identity on anything besides God produces either pride (when the idol delivers) or despair (when it fails).
- Jeremiah 17:9's warning about the deceitful heart cautions against assuming self-diagnosis of sin is easy or automatic.
Important concepts
- Idolatry — Elevating any created thing — even a good one — to the ultimate place in life that belongs to God alone.
- Incurvatus in se — Augustine's Latin phrase, "curved in on itself," describing sin as the self bent inward around its own concerns rather than oriented toward God and others.
- Disordered love — Loving good things in the wrong order or to the wrong degree — for instance, loving approval or achievement more than God — rather than loving what is inherently bad.
Related Bible references
Practical Christian application
- Ask yourself: if I lost ______ (a relationship, a career, a reputation), would my sense of self-worth collapse? That blank may name a present idol.
- Notice this week whether your anxiety, pride, or harsh judgment of others traces back to something besides God being asked to bear ultimate weight.
- Pray Psalm 139:23-24, inviting God to search your heart rather than trusting your own self-assessment.
Questions for study
Reflection questions
- What good thing in your life might currently be functioning as an idol — carrying more weight than it was built to carry?
- Do you tend toward pride when your "idol" succeeds, or despair when it fails? What does that reveal?
- How does Jeremiah 17:9 challenge your confidence in your own self-knowledge about sin?
Small-group discussion
- Why might redefining sin as disordered love, rather than a checklist, be harder to hear than a simple list of rules?
- Can your group think of a genuinely good thing (family, ministry, justice) that can still become an idol if pursued in the wrong way?
- How does this chapter's diagnosis of sin prepare the ground for the religion-versus-gospel distinction that follows?
These notes are an original UECF.NET study companion and are not a reproduction of Timothy Keller's text, which remains in copyright. Read “The Problem of Sin” in The Reason for God: Belief in an Age of Skepticism by Timothy Keller (Dutton, 2008; ISBN 978-0-525-95049-3). A catalog record for one scanned copy is available for reference at the Internet Archive (controlled digital lending — not reproduced here). Scripture quotations above are the King James Version. No quotations from Keller are included on this page. See About this Edition for full source and rights information.