This book explores the neglected significance of the doctrine of the Trinity for the understanding of human law. Through interaction with the thought of Jürgen Moltmann, Oliver O'Donovan and Thomas Aquinas, it argues that human law is called to play a positive but limited role in maintaining "shallow justice" and relative peace. Human law is overshadowed by the work of the Son, included in the purposes of the Father, and used as an instrument by the Holy Spirit. However, the Spirit works in those who are in Christ to effect "deep justice", a work of sanctification which culminates in glorification - the experience of perfect, free, willing obedience in heaven. Thinking about law in the light of the Trinity enables us to understand its role, its purpose and its limits.