Taken from NPNF (Second Series) vol 9.
In reviewing St Hilary’s thought, I will be relying primarily on Geofrey Bromiley’s Historical Theology for clarification on more difficult points. In no way can Hilary’s work be considered a literary masterpiece. It is about one hundred pages too long, repetitive, and wordy. To be fair, he wrote much of it in exile and like Augustine, was not always privy to the more mature Eastern thinking (though Hilary rectified this in some ways).
Hilary begins his theology with God’s revelation. We know God as he reveals himself to us. However, our theologizing about God will always be opaque. God is invisible, ineffable, etc., and the mind grows weary trying to comprehend him (ii.6). Language itself fails us as words are powerless (ii.7). Analogies offer some help but they only hint at the meaning (i.19).
Trinitarian theology for the church begins with the baptismal formula in St Matthew’s gospel. The Father is the origin of all; the Son is the only-begotten, and the Spirit is the gift (ii.1). As the source of all the Father has being in himself. The fullness of the Father is in the Son. Because the Son is of the Father’s nature, the Son has the Father’s nature. Hilary’s point is that like nature begats like nature.
In a break with pagan thought, Hilary distinguishes between person and nature: “nor are there two Gods but one from one” (ii.11).
Hilary and the Spirit
Did Hilary teach the Filioque? It’s hard to tell, and neither camp should draw hard conclusions. The facts are these: 1) in ii.29 the Schaff edition reads “we are bound to confess him, proceeding as He does, from Father and Son.” However, the foonote points out that there are alternative, more probably readings. It is acknowledged that throughout Hilary’s work the text has been corrupted at parts. Even asssuming the present reading to be the correct one, one must ask if by procession Hilary would mean the same thing as later Filioquist writers? The Latin word for proceed (procedere) does not have the same range as the multiple Greek words for “proceed.” Roman Catholic scholar Jean Miguel Garrigues notes that one simply can’t read English translations of the Latin semantic domains of “proceed” and from that infer, quite simplisticly, that Hilary believed in the Filioque (L’Esprit qui dit «Père!» (Paris 1981), pp. 65-75.; [no, I don’t read French. I found a link to this book on Perry’s blog, attendant with the relevant discussions).
2) Hilary goes on elsewhere to affirm that the Spirit is from the Father alone (viii.20) and the Father through the Son (xii.57); neither of these texts, obviously, are hard Filioquist reads, and in any case, this wasn’t Hilary’s point.
As an anti-Arian text, there is a reason why the Church spends more time with St Athanasius, Ambrose, and the Cappadocians. The Cappadocians and St Ambrose would later refine Hilary’s argument.
On the other hand, Hilary provides the late Western reader with a number of valuable and often stunning insights to the nature of the Church, philosophy, and the evaluations of post-Reformation traditions.
The Eucharist: St Hilary draws an analogy between the “of one nature” with Father and Son and the utter reality of the Son in the Eucharist. We receive the very Word make flesh in the Eucharist, not due to an agreement of will but because the Son took man’s nature to himself.
Denies monergism: Hilary denies there is a necessity on our will because that would impose faith on us (viii.12).
We know God by his operations or powers (later theologians would say energies): God’s self-revelation displays his Name (Person). This revelas his nature (i.27). This is what Dr Joseph Farrell calls the ordo theologiae: persons, operations, essence. The persons do things and this reveals their essence. In de Synodis para 69 Hilary warns that we must not start with the consubstantiality (or essence) when we do our Trinitarian reasoning, for this leads to confusion since the terms are not yet defined. Rather, we must begin with the Persons. (Critics of de Regnon be confounded! Hilary clearly understands the importance of starting with the Persons, not the nature).
Rejects philosophical nominalism: names correspond to realities (ix.69). Therefore, are we justified in saying something is true of the Person of Christ that is not true of the taxonomy? I admit: this isn’t Hilary’s debate, since he hadn’t yet dealt with the Calvinist take on the extra Calvinisticum. Hilary says “We must not divide Jesus Christ, for the Word was made flesh” (x.60-62). Was there an “extra” to the divine nature outside the person of Christ? Hilary doesn’t think so.
Prays to Saints: “Be with me now in thy faithful spirit, holy and blessed Patriarch Jacob, to combat the poisonous hissings of the serpent of unbelief” (v.19).
On the Rock of Matthew 16.19ff: “This faith it is which is the foundation of the Church; through this faith the gates of hell cannot prevail against her” (vi. 37). The faith of the apostles, not the see of Peter, is the foundation of the Church.
It is not a literary masterpiece, nor is it really an outstanding apologia against Arianism. However, it is a faithful reflection of the Tradition passed down, and it does give many remarkable “snapshots” of the Church’s belief which can inform, challenge, and hopefully change the minds of folk today.