St. Augustine is one of the few saints that both Catholics and (most) Protestants admire. Without a doubt, he is the most popular saint among Protestants, and is the most-cited saint in the Catechism of the Catholic Church. As such, he’s a good saint for Catholics to cite to when explaining doctrines that divide Catholic and non-Catholic Christians.
But who do you appeal to if you are St. Augustine? That is, during Augustine’s lifetime, who were the saints that he could cite, knowing that their authority and orthodoxy were nearly universally respected? Augustine actually answers that question in Against Julian, accusing Julian of going against the “many famous and brilliant holy teachers of the Catholic truth: Irenaeus, Cyprian, Reticius, Olympius, Hilary, Gregory, Basil, Ambrose, John, Innocent, Jerome, and the others.”
Of these eleven saints, there is one in particular who Augustine cites for his outspoken orthodoxy: St. Hilary of Poitiers, whose feast we celebrate today. St. Hilary was a fourth century Gallic (French) bishop known as “the Hammer of the Arians.” Augustine remarks, “Who does not know that the Gallic bishop Hilary is to be revered as the keenest defender of the Catholic Church against the heretics?”
And while Hilary is certainly less well-known than Augustine, he is revered as a saint by Catholics and Orthodox, as well as by Lutherans and Anglicans. Given all of this, it would behoove all Christians to listen to what St. Hilary has to say about issues like the Real Presence of Christ in the Eucharist.
Hilary not only believes in the physical Real Presence, he treats this fact as completely obvious to any Christian. In doing this, he sounds very much like St. Ignatius of Antioch, who used the Real Presence as proof back in the early 100s. That is, Ignatius didn’t feel a need to prove that the Real Presence was true. Instead, he started from the accepted truth of the Real Presence to prove that the Gnostics were heretics for denying the Incarnation.
We see the same thing here. St. Hilary’s opponents argue that the Father and the Son are only One in will, rather than One in Being. Hilary responds to them by showing, from the accepted fact of the Real Presence, that the union between us and the Son, and therefore between the Son and the Father, goes beyond a mere unity of wills:
“Now I ask those who bring forward a unity of will between Father and Son, whether Christ is in us to-day through verity of nature or through agreement of will. For if in truth the Word has been made flesh and we in very truth receive the Word made flesh as food from the Lord, are we not bound to believe that He abides in us naturally, Who, born as a man, has assumed the nature of our flesh now inseparable from Himself, and has conjoined the nature of His own flesh to the nature of the eternal Godhead in the sacrament by which His flesh is communicated to us? [….]
Now how it is that we are in Him through the sacrament of the flesh and blood bestowed upon us, He Himself testifies, saying, “And the world will no longer see Me, but ye shall see Me; because I live ye shall live also; because I am in My Father, and ye in Me, and I in you”[John 14:19]. If He wished to indicate a mere unity of will, why did He set forth a kind of gradation and sequence in the completion of the unity, unless it were that, since He was in the Father through the nature of Deity, and we on the contrary in Him through His birth in the body, He would have us believe that He is in us through the mystery of the sacraments?”
Hilary’s point isn’t to prove that “we in very truth receive the Word made flesh as food from the Lord.” His point is that since this is true, we know that we’re dealing with a union of natures, not just wills. But in the process of making this point about the Trinity, Hilary happens to reveal quite a bit about what the early Church believed about the Real Presence of Jesus Christ in the Eucharist. And his point is all the more powerful in that he’s making incredibly Catholic claims about the Eucharist, without feeling much of a need to defend his views:
“Hence, if indeed Christ has taken to Himself the flesh of our body, and that Man Who was born from Mary was indeed Christ, and we indeed receive in a mystery the flesh of His body—(and for this cause we shall be one, because the Father is in Him and He in us),—how can a unity of will be maintained, seeing that the special property of nature received through the sacrament is the sacrament of a perfect unity?”
How should we understand our union with Christ in the Eucharist? Hilary shows us from Scripture:
“Let us read what is written, let us understand what we read, and then fulfil the demands of a perfect faith. For as to what we say concerning the reality of Christ’s nature within us, unless we have been taught by Him, our words are foolish and impious. For He says Himself, “My flesh is meat indeed, and My blood is drink indeed. He that eateth My flesh and drinketh My blood abideth in Me, and I in him.”” [John 6:55-56]
So in the Eucharist, we aren’t just aligned as part of God’s team. We take on the Body of Christ. We become what we consume. If there was any remaining ambiguity about whether or not Hilary understood the Eucharist to be Christ’s literal, physical Body and Blood, there can be none after his next comment:
“As to the verity of the flesh and blood there is no room left for doubt. For now both from the declaration of the Lord Himself and our own faith, it is verily flesh and verily blood. And these when eaten and drunk, bring it to pass that both we are in Christ and Christ in us. Is not this true? Yet they who affirm that Christ Jesus is not truly God are welcome to find it false. He therefore Himself is in us through the flesh and we in Him, whilst together with Him our own selves are in God.”
So Hilary leaves room to deny the Real physical Presence of Christ in the Eucharist … but only if you’re ready “to affirm that Christ Jesus is not truly God.” If, on the other hand, you’re going to believe in Jesus Christ as God Incarnate, the Real Presence is an indispensable part of that faith. It seems that Hilary can’t even imagine someone denying the Eucharist while claiming to worship Jesus Christ. He leaves no room for that position, since “no man shall dwell in Him, save him in whom He dwells Himself, for the only flesh which He has taken to Himself is the flesh of those who have taken His.”
Hilary then returns to showing how the Eucharist gives evidence of the relationship of Christ to the Father:
“This is the cause of our life that we have Christ dwelling within our carnal selves through the flesh, and we shall live through Him in the same manner as He lives through the Father. If, then, we live naturally through Him according to the flesh, that is, have partaken of the nature of His flesh, must He not naturally have the Father within Himself according to the Spirit since He Himself lives through the Father?”
So that’s it: that’s the Catholic belief in the Eucharist, according to the man who Augustine described as “the keenest defender of the Catholic Church against the heretics.” I’ll leave it to you to decide if Hilary was an idolatrous heretic, or if the Real Presence of Christ’s Flesh and Blood in the Eucharist is true.