The Trinitarian Christology of St. Thomas Aquinas

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Dominic Lege, O.P.
  • Oxford, England: 
    Oxford University Press
    , February
     256 pages.
     For other formats: Link to Publisher's Website.


Although the existence of God—conceived as a single, ultimate reality that is both the ultimate efficient cause of empirical reality and its ultimate goal—is a common assumption of a variety of monotheistic religions, with the doctrine of the Holy Trinity and the doctrine of the Incarnation of the Second Person of the Trinity in Jesus Christ constituting the demarcating features of any Christian worldview and its respective stance on the origin and soteriological end of the world. However, even amongst Christians, there is no agreement on what precisely these doctrines amount to. Given that Dominic Legge’s book on Thomas Aquinas’s Trinitarian Christology is written from a Roman-Catholic point of view, my review also focuses on a Catholic understanding of the Trinity and the Incarnation.

On the doctrine of the Holy Trinity, very briefly, God is Three-in-One: God is the Father, the Son, and the Holy Spirit. While the Son proceeds eternally from the Father as the Word and Image of the Father through which the Father understands Himself completely in a single act of understanding, the Holy Spirit eternally proceeds from the Father and the Son, and is the “mutual love and nexus of the Father and the Son” (15). The Holy Spirit, thus, can be understood as the love that, of necessity, arises through the Father’s understanding of Himself in and through the Son. Although the Father, the Son, and the Holy Spirit have the same esse, their identity as distinct persons is constituted by their relational origin: The Son eternally proceeds from the Father, and the Holy Spirit eternally proceeds from both the Father and the Son. Therefore, the presence of one of the persons of the Holy Trinity entails the presence of the other two.

On the doctrine of the Incarnation—the Holy Trinity—as single, efficient cause uniting the divine nature of the second person of the Trinity, the Son, with the human nature of Jesus of Nazareth. Since this union of natures does not entail an identity of natures, Jesus Christ was both fully human and fully divine, “without any mixing or confusion of natures, and without endangering divine immutability and impassibility” (103). The reason that the Word became flesh, and made his dwelling among us—in the broader context of a Catholic worldview—is to restore God’s fallen creation. Since the Word of eternity is creation’s blueprint, it is fitting to restore a fallen creation in and through the very same blueprint on which it was created in the first place. As Legge says, “the incarnation is the divine repair project by which the image that God created in man is restored and perfected” (90). Furthermore, “Christ himself, as man, is the perfect image of God in a human nature, through whom the divine image in each of us is repaired and perfected” (92).

On the background of these articles of faith, Legge’s The Trinitarian Christology of St Thomas Aquinas provides a systematic analysis of Aquinas’s account of the Incarnation in light of the doctrine of the Holy Trinity. By careful analysis, Legge shows that in Aquinas, contrary to what theologians like Karl Rahner assumed, both the doctrine of the Holy Trinity and the doctrine of the Incarnation are deeply interwoven and, in fact, inseparable and mutually supporting: “Aquinas’s Christology is … fundamentally Trinitarian” (232). According to Legge, Aquinas was fully aware that a proper understanding of the divine missions, that is, of the fact that the Son and the Holy spirit are sent into the world for the dispensation of grace, needs to account for the Incarnation in Trinitarian terms. “The Son is constituted as a distinct divine person by his relation to the Father, which includes his relation to the Holy Spirit … and so the unique presence of the Son in his visible mission … and that mission’s disclosure of the Son’s personal identity, also necessarily implicates both the Father and the Holy Spirit … For Aquinas, then, Christ’s coming as man is from the Trinity … and is necessarily ordered to making present and revealing the Trinity in time” (232).

As it deals with a demanding topic, commonly addressed as a mystery of faith—that is, as something that could not be known—had God not decided to reveal it, Legge’s volume is a demanding book. Although formidable, Legge’s treatment of the Angelic Doctor’s Trinitarian Christology is highly rewarding for any reader interested in the core features of Christianity, and the theological rationale beyond Christian faith. Legge shows convincingly how Aquinas spells out the intrinsic relation between the doctrine of the Holy Trinity, and the doctrine of the Incarnation, as the fundamentals of a Christian account of the origin and purpose of the existence of the universe.

However, although Legge states clearly that his interest is mainly in the systematic clarification of Aquinas’s Trinitarian Christology, with which he engages in great clarity and knowledge of Aquinas’s opus, this book is lacking a systematic analysis of the contemporary relevance of Aquinas’s Trinitarian Christology. Both the doctrine of the Holy Trinity and the doctrine of the Incarnation have been extensively discussed in analytic philosophy of religion and analytic theology, and it would have been nice for the reader to see what Aquinas has had to say about these debates. This is, of course, not an objection to Legge’s enterprise as such, but rather an expression of curiosity concerning what Legge has to say about the importance of Aquinas’s Trinitarian Christology in light of recent debates on the matter.

About the Reviewer(s): 

Benedikt Paul Göcke is on the faculty of theology and religion at the Ian Ramsey Centre for Science and Religion at the University of Oxford.

Date of Review: 
July 7, 2017
About the Author(s)/Editor(s)/Translator(s): 

Dominic Legge, O.P., is assistant professor in the Pontifical Faculty of the Immaculate Conception at the Dominican House of Studies and Assistant Director at the Thomistic Institute.


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