St. Augustine’s Commentary on the Sermon on the Mount

Saint Augustine once observed that the “New Testament lies hidden in the Old and the Old Testament is unveiled in the New.” In his early years as a Manichean, St. Augustine had trouble interpreting the Bible.  Subsequently, he would acknowledge the role of his intellectual pride complicit in his prior difficulty with Scripture. After his conversion, he learned from St. Ambrose to interpret the Scriptures symbolically.  As a guiding principle for the revelation of the Scriptures’ inner spirituality, he took the Ambrosian hermeneutic: “the letter kills, but the spirit gives life.”

In time, St. Augustine came to possess a consummate spiritual acumen showing remarkable originality in biblical exegesis. By the time he wrote his Commentary on the Sermon on the Mount  in 393, he was adept at searching out the will of God revealed through the scriptures. He approached his work with the temperament of a child, rather than that of a scholar. Indeed, as a God fearing man, St. Augustine’s commentary possesses a clarity and depth that recommends it across the ages.

St. Augustine begins with the profound assertion that “anyone who piously and earnestly ponders the Sermon on the Mount—as we read in the Gospel according to Mathew—I believe he will find therein … the perfect standard of the Christian Life.” Imparted by the One True Teacher, the Sermon on the Mount elucidates the divine principles of justice guiding us to the narrow path that leads to communion with the Saints.

Appropriately, St. Augustine spends the greater part of this work devoted to a thorough treatment of the centerpiece of the Sermon: the Beatitudes. In this darkening age, the centrality of the Beatitudes in Catholic moral theology has faded from memory. The Beatitudes have come to be misunderstood moral platitudes. There is a modern tendency to project the Beatitudes as a type of social reform, lifting the poor and persecuted and accentuating a worldly peace, but St. Augustine turns our attention to the fact that they are intended to be directed inward. As Msgr. Ronald Knox said, “we are here to colonize heaven, not make things better on earth.”

St. Augustine’s commentary can turn our gaze to a proper understanding of the Beatitudes as pronouncements of the perfect moral law that were hidden in the Old Testament and unveiled by Christ in the New Testament. The Beatitudes are the embodiment of Catholic moral theology.  St. Thomas refines the moral end of St. Augustine’s ethic by explaining that “to possess God in full in the beatific vision is to have our powers fully realized, fully perfected, and to find them at rest, in perfect happiness for all eternity.”

St. Augustine explains that the first seven Beatitudes are the “maxims on which the Lord based this entire Sermon.” He draws a distinction between the first seven and the eighth. He tells us “there are seven maxims which constitute perfection.” These first seven are a free will choice to follow. The eighth is done to us in consequence of choosing the first seven. The eighth proclaims “Blessed are those who are persecuted for righteousness’ sake, for theirs is the kingdom of heaven.” Our labor entails cooperating with grace to cultivate the virtues that facilitate the attainment of the first seven beatific precepts and then to allow the eighth Beatitude to perfect us through redemptive suffering. St. Augustine explains that “the profitable thing is not suffering those evils, but bearing them with equanimity and cheerfulness for the sake of Christ.”

St Augustine shows how Christ unveiled the law hidden in the Old Testament by elucidating the relationship between the Beatitudes, virtues and the gifts of the Holy Spirit enumerated by the prophet Isaiah. In 11:2-3 he speaks of the coming of Christ: “the spirit of the Lord shall rest upon him, the spirit of wisdom and understanding, the spirit of counsel and might, the spirit of knowledge and the fear of the Lord.” Christ came to fulfill the law and the prophets and in the Beatitudes He reveals the law hidden in the Prophet’s account of those seven operations of the Holy Spirit.

Isaiah begins by attributing to the Christ the highest spiritual gift of wisdom and the gifts descend in order to the fear of God. In His Sermon, Jesus puts them in human order from the lower active and exterior to the higher introspective and interior. He begins with the fear of the Lord as the first step of the ascent to the final end of wisdom demonstrating that the Beatitudes embody the properly ordered mystical hierarchy of the climb to sanctity.

St. Thomas defines the Beatitudes as “perfect works emanating from virtues perfected by the gifts” of the Holy Spirit. St. Augustine orders and clarifies the relationships between the beatific precepts and their corresponding spiritual gifts. Poverty of spirit corresponds with fear of the lord in which all wisdom begins. Meekness corresponds with piety, honor for the sacred Scriptures and the restrained power to live them out. Mourning corresponds with the gift of knowledge and facilitates the discernment of good from evil. Hunger and thirst for justice corresponds with the gift of fortitude to be truly just. Mercy coincides with the gift of counsel which exhorts us to forgive as we wish to be forgiven. Purity of heart corresponds with the gift of understanding what the eye has not seen and the ear has not heard. Peacemaking corresponds with the gift of wisdom. St. Augustine explains that “for with peacemakers all things are in proper order, and no passion is in rebellion against reason, but everything is in submission to man’s spirit because that spirit is obedient to God.”

Here is but a foretaste of the feast for the soul, available to the spiritual reader of St. Augustine’s insightful exegesis of the Sermon on the Mount. The Church Doctor exhorts us to heed Christ’s words as he closes His Sermon: “Everyone therefore who hears these words of mine and acts according to them, I shall liken him to a wise man who builds his house on a rock.”  When the storms of life come, the house stands. The alternative is to build our house on the shifting sands of the secular world. As G.K. Chesterton quipped, “There are an infinite number of ways to fall, but there is only one way to stand.” The one way to stand up straight as a citizen of the City of God is by that perfect standard of Christian living, the Beatitudes, hidden in the Old Testament and revealed to us in the New through the Sermon on the Mount.

Editor’s note: This article originally appeared on Crisis Magazine and is reprinted here with kind permission. 

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Steven Jonathan Rummelsburg is the executive director of the 7 Institutes at the Veritatis Splendor HQ project. He is a senior fellow at The American Principles Project and a senior fellow at The Cardinal Newman Society. He is on the Teacher Advisory Council at Sophia Institute Press for teachers where he has written Catholic curriculum for the past 8 years, he also serves on the advisory council for Aquinas Learning. Steven is a writer and speaker on education, culture, and the Faith.

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