The Keys to Spiritual Growth treats the means by which Christians actually grow. John MacArthur works through obedience and its relation to love, the confession of sin, the filling of the Spirit, the place of Scripture and prayer, the mortification of sin, the role of suffering in maturity, and the fellowship of the church, arguing that growth is neither automatic nor mysterious but tied to appointed means.

The book suits newer believers wanting a map of the Christian life, longer-standing Christians who have plateaued, and small groups studying sanctification. MacArthur writes against the expectation of a shortcut or a secret, which is precisely what makes the book useful to anyone who has looked for one.