A Disruptive Witness: Intellectual Disability and the Christian Life develops a constructive theological account of the Christian witness of people with intellectual disabilities. Rempel proposes that people with intellectual disabilities witness to the God who has acted in history on our behalf, as they are empowered by God to do so. Finding an ally in Karl Barth's theology of witness, the claim of this book is not that Christians need to find new ways to empower people with intellectual disabilities in the practice of witness, but rather levies a challenge to Christians to presume that people with intellectual disabilities are currently witnessing even today. It is thus a call to pay attention to the mysterious ways God may be at work through people with intellectual disabilities.

The book is developed in two parts. The first part sets forth "the ontology of witness," or what God instantiates in the life of the believer in order to make witness possible. Rempel demonstrates how the Christian is called by God into a life of participating in Christ, and it is this calling and participation which enable the task of witness. Then, the second part develops "the activity of witness," which tracks the centrifugal motion of witness, working outwards from one's participation in Christ as they are thrust into the public sphere. In doing so, Rempel shows not only how it is possible for people with intellectual disabilities to witness, but how this witness occurs (and is occurring) all around us, if only we might pay attention.