Summa Theologiae

Pope Benedict XVI’s weekly catechesis.

During his general audience on June 23, Pope Benedict XVI continued his catechesis on St. Thomas Aquinas. He spoke about Aquinas’ monumental work, the Summa Theologiae, which reflects his serene confidence in the harmony of faith and reason and in the ability of reason, enlightened by faith, to come to an understanding of God and his saving plan.

After presenting an overview of the theological truths of Aquinas’ masterpiece, the Holy Father pointed out that these great theological truths are also reflected in St. Thomas’ preaching. In a clear and simple way, Aquinas presented to his students and to the faithful around him the mysteries of faith, the content of prayer, and the demands of a moral life shaped by natural law and the Gospel’s commandment of love.

Dear brothers and sisters,

Today I would like to complete my teaching on St. Thomas Aquinas with this third talk in the series.

Even now, more than 700 years after his death, we can learn much from him.

My predecessor, Pope Paul VI, reminded us of this in a talk he gave in Fossanova on Sept. 14, 1974, on the 700th hundred anniversary of St. Thomas’ death. He posed the following question: “Master Thomas, what can you teach us?”

His answer was as follows: “To trust in the truth of Catholic religious thought, which he defended, expounded and laid open to the human mind’s understanding” (Insegnamenti di Paolo VI, XII [1974], pp. 833-834).

That same day, in the town of Aquino, still speaking of St. Thomas, he said: “Everyone, insofar as they are faithful sons and daughters of the Church, can and must be his disciple, at least to some extent” (Ibid, p. 836).

Therefore, let us, too, enter into St. Thomas’ school and into his masterpiece, the Summa Theologiae. Though he never finished it, it is still a monumental work of 512 questions and 2,669 articles.

It consists of very concise reasoning in which human intelligence is applied to the mysteries of the faith in a clear and profound way, weaving together questions and answers in which St. Thomas delves into the teachings of sacred Scripture and the Fathers of the Church — especially St. Augustine.

In his reflections on genuine questions of his time that are often the same questions we have, St. Thomas uses the thought and methods of the ancient philosophers as well, especially Aristotle. St. Thomas’ precise, clear and relevant maxims outline the truths of the faith; truth is the gift of the faith, shining forth and becoming accessible to us for reflection.

Nevertheless, this effort of the human mind — as St. Thomas Aquinas reminds us through the example of his own life — must always be illuminated by prayer, by the light that comes from on high. Only the person who lives with God and with his mysteries can understand what they are saying.

God’s Existence

In his Summa, St. Thomas starts from the fact that there are three different ways in which it can be said that God “is.”

God is, existing, in himself. He is the beginning and the end of all things, so all creatures come from and depend on him. Secondly, God is present through his grace in the life and work of Christians, of the saints.

Finally, God is present in a most special way in the person of Christ united to the man Jesus, and at work in the sacraments, which flow forth from his work of redemption.

For this reason, the structure of this monumental work (see Jean-Pierre Torrell, La Summa di San Tommaso, Milan 2003, pp. 29-75) — done with a “theological look” at the fullness of God (see Summa Theologiae, Ia, q. 1, a. 7) — is divided into three parts. St. Thomas — the Doctor Communis — himself describes it in the following words: “Because the chief aim of sacred doctrine is to teach the knowledge of God, not only as he is in himself, but also as he is the beginning of things and their last end, and especially of rational creatures, as is clear from what has been already said, therefore, in our endeavor to expound this science, we shall treat first of all of God; secondly, of the rational creature’s advance towards God; and thirdly of Christ, who as man, is our way to God” (Ibid, I, q. 2).

It is a circle: God in himself, who comes out of himself, takes us by the hand so that with Christ we return to God, we will be united to God, and God will be all in all.

The Three Parts

The first part of the Summa Theologiae is, therefore, a study of God himself, of the mystery of the Trinity and of God’s creative work. We also find in this part a profound reflection on the true nature of the human person insofar as he is the work of God’s hands, the fruit of his love.

On the one hand, we are created beings, dependent on God; we do not come from ourselves. On the other hand, however, we have genuine autonomy so that we are not merely something apparent, as some Platonic philosophers claim, but something real, willed by God as such, and with value in itself.

In the second part, St. Thomas reflects on man, impelled by grace, in his desire to know and to love God in order to be happy in time and in eternity.

First, the author presents the theological principles of moral conduct, studying how reason, will and passions work together in man’s free choice to do good, to which is added the strength of the grace that God gives him through the virtues and the gifts of the Holy Spirit, as well as the help that moral law offers.

Thus, the human being is a dynamic being who seeks himself, who seeks to become himself and who seeks, in this regard, to carry out works that will build him as such and that will make him truly human.

This is where moral law enters the picture, where grace and reason, the will and the passions enter the picture. Upon this foundation, St. Thomas builds a description of the character of the man who lives according to the Spirit and thus becomes an icon of God.

St. Thomas Aquinas pauses at this point to study the three theological virtues — faith, hope and charity — followed by a close analysis of more than 50 moral virtues that are organized around the four cardinal virtues — prudence, justice, temperance and fortitude. He then ends with a meditation on the various vocations within the Church.

In the third part of the Summa, St. Thomas studies the mystery of Christ, who is the way and the truth and through whom we can be reunited with God the Father.

In this section, he writes in a practically unmatched way on the mystery of Jesus’ incarnation and passion, adding a large section on the seven sacraments, through which God’s incarnate Word offers us all the graces of his incarnation for our salvation and for our journey of faith towards God and towards eternal life, and dwells in an almost material way with the reality of creation, thereby touching our inmost being.

The Sacraments

When he speaks of the sacraments, St. Thomas reflects in a particular way on the mystery of the Eucharist, for which he had a very great devotion, to the point that, according to biographers of old, he used to lean his head against the tabernacle, as though he could hear the divine and human heart of Jesus beating.

In one of his commentaries on Scripture, St. Thomas helps us to understand the excellent merit of the sacrament of the Eucharist, when he writes: “Since this is the sacrament of Our Lord’s passion, it contains in itself Christ who suffered. Thus, whatever is an effect of Our Lord’s passion is also an effect of this sacrament. For this sacrament is nothing other than the application of Our Lord’s passion to us” (In Ioannem, c.6, lect. 6, n. 963).

We can very well understand why St. Thomas and other saints, as they celebrated Mass, shed tears of compassion for the Lord, who offers himself as a sacrifice for us, tears of joy and of gratitude.

Dear brothers and sisters, let us follow the example of the saints and love this sacrament! Let us participate with devotion at Mass in order to obtain its spiritual fruits. Let us feed upon the body and blood of Our Lord so that we may be unceasingly nourished by his divine grace! Let us willingly and frequently spend time with the Blessed Sacrament, one on one!

Preaching and Teaching

What St. Thomas explained with academic rigor in his major theological works, such as the Summa Theologiae and the Summa Contra Gentiles, was also expressed in his preaching, which he directed both to his students and the faithful.

In 1273, a year before his death, he preached throughout Lent in the Church of San Domenico Maggiore in Naples. The content of those sermons was collected and preserved in a series of booklets in which he explains the Apostles’ Creed, interprets the Our Father, illustrates the Ten Commandments, and comments on the Hail Mary.

This series of preaching of the “Angelic Doctor” corresponds almost in its entirety to the structure of the Catechism of the Catholic Church.

Indeed, in a time of renewed commitment to evangelization such as our own, our catechesis and preaching must always include these fundamental themes: what we believe, namely the Creed; how we pray, namely the Our Father and the Hail Mary; and the way we live as biblical revelation teaches us, namely the law of love of God and of our neighbor as well as the Ten Commandments, which are an explanation of this mandate of love.

I would like to offer some simple, essential and convincing examples of the content of St. Thomas’ teaching. In his brief booklet Devotissima Expositio Super Symbolum Apostolorum, he explains the importance of faith. Through it, he says, the soul is united to God, producing something akin to the seedling of eternal life. Life is given a clear direction, and we can easily overcome temptations.

To those who object that faith is absurd because it leads us to believe in something that we do not experience with our senses, St. Thomas offers a very detailed response, reminding us this is a fallacious objection, because the human intellect is limited and cannot know everything. It would be foolish to accept truth purely out of faith only if we were able to have perfect knowledge of all things visible and invisible.

Moreover, as St. Thomas observes, it would be impossible to live without trusting the experience of others, in matters to which our personal knowledge does not extend. Thus, it is reasonable to have faith in God who reveals himself and in the testimony of the apostles. They were few — simple and poor — and distraught over the crucifixion of their teacher, and yet many wise, noble and rich people were converted in a short period of time after hearing them preach. Indeed, it is an astonishing phenomenon to which history can give no reasonable answer other than that of the apostles’ encounter with the risen Lord.

Commenting on the article of the Creed concerning the incarnation of the divine Word, St. Thomas offers some reflections. He says that Christian faith is reinforced in light of the mystery of the Incarnation.

Hope grows in trust when we consider that the Son of God came among us as one of us to communicate his divinity to mankind. Charity is enlivened because there is no more evident sign of God’s love for us than to see the Creator of the universe himself become a creature, one of us.

Finally, when reflecting on the mystery of God’s incarnation, we are enflamed with a desire to join Christ in his glory. Using a simple and effective analogy, St. Thomas observes: “If the brother of a king were far away, he certainly would long to be able to live next to him. Christ in fact is our brother. Therefore, we must desire his company and to become one heart with him” (Opuscoli teologico-spirituali, Rome, 1976, p. 64).

In his discussion of the Our Father, St. Thomas demonstrates that this prayer is perfect in itself, having all the five characteristics that a well-made prayer should have: trusting and peaceful abandonment; content that is appropriate because, as St. Thomas observes, “it is quite difficult to know exactly what it is appropriate to ask and what not, when we experience difficulty choosing between desires” (Ibid, p. 120); as well as requests made in the appropriate order, with fervent love and sincere humility.

St. Thomas was, like all the saints, greatly devoted to the Blessed Virgin. He gave her a marvelous title: Triclinium totius Trinitatis, in other words, the place where the Trinity finds repose because, thanks to the Incarnation, the three divine Persons dwell within her as in no other creature and experience the delight and the joy of living in her soul full of grace. Through her intercession we can obtain any kind of help.

May we, too, pray a prayer that is traditionally attributed to St. Thomas and that, in any case, reflects the character of his deep Marian devotion: “O blessed and sweet Virgin Mary, Mother of God ... I entrust my whole life to your merciful heart. ... Obtain for me, my sweet Lady, true charity, with which I can love with all my heart your most holy Son and you, after him, above all things, and my neighbor in God and for God.”

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