Augustine's differences with Pelagius over human nature lead him to redefine the role of grace in mediating knowledge and love of justice within the soul. Against Pelagius and his associates, he insists that all intellectual activity which aims at understanding virtue depends upon Christ's union with the soul. In Chapter 3 we observed that Augustine's primary model for the just society makes use of the Pauline image of Christ as ‘head of the body, which is the church’ (Col 1:18, 1:24). Within this image of the body, Augustine was also seen to describe a dialogue between Christ and his members, through which he mediates virtue to the soul. Furthermore, we saw that this dialogue depends in Augustine's thought on the concept of unity ‘in one person’, through which he explains the union of Christ's divine and human natures. In this chapter, we shall see how Augustine draws upon this complex image of Christ's divine—human dialogue to explain the relationship he assumes between two sets of exegetical categories: examples and sacraments, and knowledge and wisdom. For Augustine, human knowledge (scientia) regarding what the scriptures reveal about virtues such as justice requires a transformation by divine wisdom (sapientia), which is analogous to the transformation of Christ's human nature through its union with his divine nature. It will be shown here that Augustine posits this same transformation between scriptural examples and sacraments.