This paper investigates the specific roles that Augustine assigns respectively to Christ and the Holy Spirit in the mediation of virtues to Christians. At timesAugustine speaks about Christ’s mediation of virtues without mentioning the Holy Spirit, while at other times he asserts that the Holy Spirit endows the human soul with virtue, without explaining how the Spirit’s activity is related to Christ’s. This paper focuses on the logic behind these twin aspects of mediation as far as the Christian’s continual growth in virtues is concerned.