Born around A.D. 300, in Poitiers (today, France), Saint Hilary was a member of an affluent pagan family and was well educated, even learning Greek, which at the time was disappearing from Western Europe. After his formal education, Saint Hilary took up the study of Scripture. Reading Exodus 3:14 ("I am who am."), Saint Hilary is reported to have said "I was frankly amazed at such a clear definition of God, which expressed the incomprehensible knowledge of the divine nature in words most suited to human intelligence." Moving onward to a study of the New Testament, Saint Hilary came to learn of Our Lord and learned that the point of life was not death, but a life eternal with Christ, which He offers to all of us through his passion, death, and resurrection. "No longer did it look upon the life of this body as troublesome or wearisome, but believed it to be what the alphabet is to children . . . namely, as the patient endurance of the present trials of life in order to gain a blissful eternity."
His conversion of heart now complete, Saint Hilary was baptized and joined the Church. After his baptism, so well known was he for his Christian life and zeal that, even though married with a child (whose name appears to have been Abra), Saint Hilary was elected Bishop of Poitiers in about A.D. 353. As bishop, Saint Hilary had to confront the significant challenge of the Arian heresy, ravaging the Church at the time, which denied the divinity of Jesus Christ. In fact, the Emperor Constantius II, and many local bishops, were Arians. When the Synod of Biterrae was called in A.D. 356 to justify Arianism, Saint Hilary defended the true teaching of the Chrurch--that Jesus Christ was true God and true Man--and rebuked Emperor Constantius II for his Arian beliefs. In turn, Saint Hilary was exiled to Phrygia (today, Turkey) for nearly four years.
During his time in exile, Saint Hilary continued to study and began writing, continuing to administer his diocese from Phrygia. In his writings there are several important works that still exist, including On the Trinity, a commentary on the Gospel of Matthew, and a commentary on the Psalms. In his writing on the Holy Trinity, Saint Hilary says: "For one to attempt to speak of God in terms more precise than he himself has used: to undertake such a thing is to embark upon the boundless, to dare the incomprehensible. He fixed the names of His nature: Father, Son, and Holy Spirit. Whatever is sought over and above this is beyond the meaning of words, beyond the limits of perception, beyond the embrace of understanding."
After a period of time in exile, Saint Hilary had caused such an inconvenience to the Emperor that he was sent back to his diocese, which he appears to have reached in about A.D. 361 shortly after the ascension of Emperor Julian. On his travels back home, Saint Hilary made his way through Greece and Italy and learned of the hymns being used by the Arians as propaganda, Once Saint Hilary reached his diocese, he set to work on Latin hymns to propagate the true teaching of the Church. For this reason, Saint Hilary is sometimes today still referred to as the first Christian Latin hymn writer, although none of hymns today attributed to Saint Hilary can be verified as having been written by him.
In his diocese Saint Hilary continued to create problems for those opposed to the true teaching of the Church, and in about A.D. 364 or 365 Saint Hilary went to Milan to assail the Bishop of Milan for being an Arian. However, Emperor Valentinian protected the bishop of Milan and ordered that Saint Hilary be removed from the city.
In A.D. 365, Saint Hilary published the Contra Arianos vel Auxentium Mediolanensem liber, in connection with the Milan controversy. Saint Hilary's later life was spent in relative quiet, working on his commentary on the Psalter. Toward the end of his episcopate, Saint Hilary encourage Saint Martin of Tours to found a monastery in his diocese.
Saint Hilary died in A.D. 368. After his death, the cult of Saint Hilary developed in association with that of Saint Martin of Tours. In 1851 Blessed Pope Pius IX declared Saint Hilary to be a doctor of the Church.
In his general audience on 10 October 2007, Pope Benedict XVI gave a catechesis on Saint Hilary, from which we learn more of the theology of Saint Hilary:
To sum up the essentials of his doctrine, I would like to say that Hilary found the starting point for his theological reflection in baptismal faith. In De Trinitate, Hilary writes: Jesus "has commanded us to baptize in the name of the Father and of the Son and of the Holy Spirit (cf. Mt 28: 19), that is, in the confession of the Author, of the Only-Begotten One and of the Gift. The Author of all things is one alone, for one alone is God the Father, from whom all things proceed. And one alone is Our Lord Jesus Christ, through whom all things exist (cf. I Cor 8: 6), and one alone is the Spirit (cf. Eph 4: 4), a gift in all.... In nothing can be found to be lacking so great a fullness, in which the immensity in the Eternal One, the revelation in the Image, joy in the Gift, converge in the Father, in the Son and in the Holy Spirit" (De Trinitate 2, 1). God the Father, being wholly love, is able to communicate his divinity to his Son in its fullness. I find particularly beautiful the following formula of St Hilary: "God knows not how to be anything other than love, he knows not how to be anyone other than the Father. Those who love are not envious and the one who is the Father is so in his totality. This name admits no compromise, as if God were father in some aspects and not in others" (ibid., 9, 61).
For this reason the Son is fully God without any gaps or diminishment. "The One who comes from the perfect is perfect because he has all, he has given all" (ibid., 2, 8). Humanity finds salvation in Christ alone, Son of God and Son of man. In assuming our human nature, he has united himself with every man, "he has become the flesh of us all" (Tractatus super Psalmos 54, 9); "he took on himself the nature of all flesh and through it became true life, he has in himself the root of every vine shoot" (ibid., 51, 16). For this very reason the way to Christ is open to all - because he has drawn all into his being as a man -, even if personal conversion is always required: "Through the relationship with his flesh, access to Christ is open to all, on condition that they divest themselves of their former self (cf. Eph 4: 22), nailing it to the Cross (cf. Col 2: 14); provided we give up our former way of life and convert in order to be buried with him in his baptism, in view of life (cf. Col 1: 12; Rom 6: 4)" (ibid., 91, 9).
Fidelity to God is a gift of his grace. Therefore, St Hilary asks, at the end of his Treatise on the Trinity, to be able to remain ever faithful to the baptismal faith. It is a feature of this book: reflection is transformed into prayer and prayer returns to reflection. The whole book is a dialogue with God. I would like to end today's Catechesis with one of these prayers, which thus becomes our prayer:
"Obtain, O Lord", St Hilary recites with inspiration, "that I may keep ever faithful to what I have professed in the symbol of my regeneration, when I was baptized in the Father, in the Son and in the Holy Spirit. That I may worship you, our Father, and with you, your Son; that I may deserve your Holy Spirit, who proceeds from you through your Only Begotten Son... Amen" (De Trinitate 12, 57).