Our Sufficiency in Christ argues that everything the believer needs for life and godliness is found in Christ, and that the church repeatedly looks elsewhere. John MacArthur identifies three substitutes in particular, pragmatic method borrowed from business and marketing, secular psychology offering a parallel account of the human heart, and mysticism that seeks revelation beyond Scripture, and sets each against the biblical doctrine of what Christ has already supplied.

The book suits believers wearied by programmes and techniques, pastors weighing what to adopt from the surrounding culture, and anyone who has been told that the Bible needs supplementing to address real problems. MacArthur's argument is doctrinal rather than merely reactive, grounding sufficiency in the person and work of Christ Himself.