Jack Mahoney opens this engaging and illuminating work with a clear statement of intent. His book begins:

What follows is elegantly written, carefully researched, and tightly argued. According to Mahoney, Aquinas sees an ‘affinity’ between the internal relations of the Trinity and the external missions in the economy. On this basis Mahoney shows how Aquinas ‘appropriated’ created effects to the Spirit through an analysis of biblical images such as wind, fire, water, and oil. A picture emerges of the Spirit as a recreating principle of life who both leads us to Christ and drives us out on mission.

A key text in this dynamic presentation is Romans 8: 14: ‘for all who are led by the Spirit of God are children of God’. Aquinas, according to Mahoney, understands the children of God to be not just led but ‘driven’ by the Spirit. The Spirit provides an impetus to human action that is not external but internal to the subject. Here Mahoney argues forcefully against translating Aquinas's ‘instinctus’ as ‘instinct’, preferring instead ‘instigation’. The action of the spiritual person is instigated by the Spirit. Mahoney excludes any sense that this ‘instigation’ might replace or coerce the free choice of the subject. Instead, Mahoney attempts to capture the idea that for Aquinas the grace of the Holy Spirit elevates the powers of the soul by establishing a proportionality between the mover and the moved. An animal is governed by its instincts, but the children of God are inclined to act in such a way that we freely choose to obey God's will.

This conclusion leads Mahoney into an analysis of Aquinas's teaching on the New Law. This New Law, for Aquinas, is the grace of the Holy Spirit. Predominantly, then, the New Law is unwritten. Nevertheless, in a secondary sense it includes written elements which have themselves been inspired or instigated by the Spirit. These written elements (which include both the Scriptures and the Church's expounding of the Scriptures in doctrine and law) offer general principles. It is the task of the spiritual person to apply these general principles to the reality of their everyday lives under the impetus of the Spirit. To this end, the Spirit moves the spiritual person through a medium that he himself has established within them: the infused virtues and the gifts.

There are not, then, two laws but one law which has both written and unwritten dimensions. Mahoney acknowledges that Aquinas says little about how these two dimensions interact, and so he extrapolates from Aquinas's comments on Romans 8: 26: ‘the Spirit helps us in our weakness; for we do not know how to pray as we ought’. Aquinas, Mahoney argues, imagines the Spirit instigating human acts by perfecting a normal process of human reasoning with this difference: the spiritual person takes counsel with God through the medium of the gifts and implements this counsel under the impetus of the Spirit. The Spirit therefore perfects the intellect such that the general principles manifested in the written law under the inspiration of the same Spirit are applied appropriately in any given circumstance.

Aquinas's argument, then, rests on the idea that the gift of charity imparted by the Spirit offers the spiritual person a certain connaturality with God. Through this influx of grace charity spills out from the will into the intellect where it takes the form of wisdom. Empowered by this gift of wisdom, the spiritual person begins to share God's perspective on creation: she gains a more profound insight into God's providential ordering of her life; she grasps more clearly what the written law aims to achieve and how it might be implemented. Christian wisdom, then, concerns the proper ordering of human life in all its dimensions. Mahoney is therefore critical of thinkers such as Thomas Gilby for translating Aquinas's prudentia as ‘practical wisdom’. This does not, Mahoney argues, do justice to the place of wisdom in Aquinas's thought. Wisdom, properly speaking, is not synonymous with prudence, it is the consequence of loving God: it is the spilling out into the intellect of divine charity.

The importance of Mahoney's distinction between wisdom and prudentia becomes clearer when we remember that Aquinas does not offer us a model or method of ‘discernment’. Instead, Mahoney argues, ‘the purpose of wisdom is to be discerning rather than discerned’ (p. 146). Romans 12: 2 is a key text here: ‘Do not be conformed to this world, but be transformed by the renewing of your minds, so that you may discern what is the will of God’. The connaturality with divine wisdom gained through the gift of charity grants the spiritual person a ‘taste’ for divine wisdom. The idea is straightforward: If we possess something in common with what we are considering, then we have an inherent capacity to recognise what we are looking for. On this basis Mahoney rejects attempts to translate Aquinas's ‘discretio’ not as ‘discernment’ but as ‘discretion’ in the hope of more readily connecting this notion with a more Aristotelian idea of prudentia. Again, this conflation of wisdom and prudentia is for Mahoney a distortion. For Aquinas, to lack wisdom is analogous to lacking a healthy sense of taste, Ecclesiasticus 6: 21 in the vulgate being a useful summary of his thinking: How bitter wisdom is to the untaught. The child of God, in contrast, whose mind has been renewed by the grace of the Holy Spirit has acquired a taste for God's will. For the spiritual person, the wisdom of God can be discerned and recognised in much the same way as the palate of someone in good health can detect flavour.

Aquinas is clear that all those in a state of grace receive the Spirit to an extent that is sufficient for their salvation. Nevertheless, few are wise enough to gain a really penetrating insight into the ends and purposes of God in their life. In some circumstances we need extra help. This brings us to the final dimension of the emerging synthesis of wisdom identified by Mahoney in the writings of Aquinas: ‘the word of wisdom’. This is a supplementary gift which enables a person to grasp and manifest to others the higher mysteries of God's wise and providential ordering of creation. In addition, then, to the written law promulgated under the instigation and inspiration of the Spirit, and the personal graces which enable a spiritual person to be wise in their application of these general principles, the New Law also contains a charismatic gift given to some that all might be wise.

Mahoney concludes by noting that this synthetic cycle of Wisdom dovetails neatly with the biblical (and Aristotelian) notion of order that was so central to patristic and medieval thinking. When human creatures creatively act, prompted by the Spirit via the gifts of the same Spirit, they play an active role in God's wise providential ordering of creation. Thus, the arc of this thoroughly theological presentation of Aquinas's moral thinking that began with the immanent Trinity now concludes only 164 pages later in a celebration of God's creation. On the way, Mahoney presents a compelling portrait of Aquinas as a biblical and Trinitarian theologian who understands the missions of the Son and the Spirit to be central to the Christian moral life. This is an excellent book.