Brendan Harris: ‘Where the Sanctification is One, the Nature is One’: Pro-Nicene Pneumatology in Ambrose of Milan’s Baptismal Theology.

Appeals to the Spirit’s baptismal function are a common strategy in pro-Nicene defences of the Spirit’s divinity. The role of these arguments in the eventual triumph of pro-Nicene theology has been well-documented by such scholars as R. Williams, L. Ayres and C. Beeley. However, their influence on developments in sacramental theology is less well-documented. This paper explores the influence of pro-Nicene trinitarian thought on fourth century sacramental theology by analysing Ambrose of Milan’s account of the Spirit’s sanctifying function in baptism.

Building on the work of L. Ayres (Oxford, 2006; Augustinian Studies, 2008; Dublin, 2010), this paper will identify two strands of pro-Nicene thought which shape Ambrose’s account of the Spirit’s sanctifying activity. The first of these is the argument from inseparable operations. In On the Holy Spirit (De Spir.) 1.62-64, 66, 90-94 Ambrose describes sanctification as one inseparable act of divine sending, in which the Spirit is sent by the Father through the Son into the hearts of believers.
Secondly, Ambrose’s account of the effects of sanctification is shaped by the doctrine of the Holy Spirit as undiminished giver. The Spirit’s sanctification enables believers to become partakers of the divine nature (De Spir.1.79-80, 3.90-93). The love of God is also communicated to believers through sanctification by virtue of the Spirit’s unity with the divine nature. (De Spir.1.66, 92-94).

By analysing Ambrose’s account of the Spirit’s sanctifying role in baptism, therefore, this paper hopes to draw out an under-appreciated theological ramification of the trinitarian controversies of the fourth century.