The One Christ: St. Augustine's Theology of Deification
The Holy Spirit's Indwelling 155 soul can participate in the very substance of God? Similar to his use of deificare, this is unfortunately an area where he is not concerned to provide a clear resolution or to offer some philosophical solution. Once again, he is much more content to exhort than to explain.
However, while Augustine may not care to venture into the dynamics of how humanity and divinity can meet, we accept that it is an act of grace which is the only action that will bring the human person to completion. This is Augustine's central concern. For his main goal in developing the Pauline language of the human soul as God's dwelling place or in arguing that true human happiness comes only through participation in the very substance of God is to show that Christianity never forces the sanctified creature to rest in some created gift. The life of the holy ones consists in living contact with the divine nature. He thus appears to be taking a middle path between violating or modifying the divine nature and understanding the divine presence simply in terms of an operation extrinsic to the created person. Perhaps this point will be made clearer by turning to what proves to be more of a theological treatise on the presence of God than a simple letter, Augustine's Epistula 187 to Dardanus.48
In the year 417 Augustine finally makes time to answer a couple of difficult questions posed to him by the Gallic prefect of the praetorium, Cornelius Postumus Dardanus. Dardanus is already a practicing Christian and finds himself puzzled over (1) how Christ can promise the good thief paradise since he was still to descend into the underworld (ep. 187.1.1–6.21); and (2) how John could have leapt in the womb at his Lord's arrival (ep. 187.7.22-13.41). Augustine answers both of these queries by distinguishing between God's ubiquitous presence and God's indwelling in those Christians whom he makes his own.
48. Augustine will later revise the name of ep. 187 to De Praesentia Dei liber; cf., retr. 2.49.