What do the saints say about justice? Before it became a political slogan or an outcry against the wrongs of the world, justice is, for the Catholic tradition, a cardinal virtue: the firm and constant will to give each one what is due to him. The saints did not merely praise this virtue; they defined it, described its structure, and above all they lived it — in court, on the throne, beside the poor. This article gathers their powerful words, from the Church Fathers to the scholastic doctors, and lets them speak.
The thread that unites them all is a reversal: the world calls “justice” the claim of one’s own rights; the saints call justice the exact payment of one’s debts. Saint Augustine defines it as love that serves only God; Saint Ambrose affirms that in giving to the poor one does not perform almsgiving but restores; Saint Thomas makes it the highest of moral virtues; Saint Gregory the Great reminds us that aiding the needy is first “paying a debt of justice.” From these voices emerges a common, firm, and coherent doctrine, which this article presents.
This selection is devoted to the own voice of the saints. For the practical path — how to grow in this virtue, its species according to Saint Thomas, the means and pitfalls — see How to Grow in Justice. For the divine attribute — the Justice of God and its relation to Mercy — see God of Justice and Mercy. For common misunderstandings — justice reduced to legalism, vengeance, or claims — see Common Errors Regarding Justice.
“To render to each his due”: the formula the saints received and transmitted
The first thing the saints did was to gather a definition — not to invent one. The most enduring formula comes from Roman law, from the jurist Ulpian: iustitia est constans et perpetua voluntas ius suum unicuique tribuens. Saint Thomas Aquinas takes it up as is at the beginning of his treatise on justice, and the Church makes it her own language:
“Justice is the constant and perpetual will to render to each his due.”
— Ulpian, Digest I, 1, 10, quoted by Saint Thomas Aquinas, Summa Theologica, II-II, q. 58, a. 1[1]
This definition is not neutral: by baptizing it, the saints give it a new center. The “each” to whom one must render what is due begins with God, to whom man owes everything. The Catechism will take up its substance: “Justice is the moral virtue that consists in the constant and firm will to give God and neighbor what is their due.”[2]
Saint Thomas: the proper act of justice
For Saint Thomas, justice is recognized by its act: not a feeling, but an operation. The proper act of justice is to render to each what is his — a terse formula that immediately excludes justice as spectacle:
“The proper act of justice is nothing else than to render to each what is his.”
— Saint Thomas Aquinas, Summa Theologica, II-II, q. 58, a. 11[3]
The Angelic Doctor draws from this a consequence that the saints have continually pondered: justice resides in the will, not in sensibility; it does not measure what I feel, but what I give. And because it regards the good of another — a good broader than my own — it is, he says, the most excellent of the moral virtues:
“Justice is the most excellent of the moral virtues, for it resides in the will and has for its object the good of another.”
— after Saint Thomas Aquinas, Summa Theologica, II-II, q. 58, a. 12[4]
Saint Augustine: justice is first love of God
Where the jurist looks at the act, Saint Augustine goes back to the root. Defining the four cardinal virtues as so many faces of love of God, he gives a definition of justice of unparalleled depth:
“Justice is the love that serves only God, and which, for that reason, rightly governs all the rest, in what is subject to man.”
— Saint Augustine, The Morals of the Catholic Church, I, 15, 25[5]
The scope is immense: if justice is a form of love, then it is never separable from charity. To render to God what is due is to love Him as God; and it is from this first love that the just order of all life flows. The saints who follow — Thomas, Gregory, Ambrose — will add only clarifications to this intuition: true justice has its source above.
The First Justice: Giving to God What Is God’s
The modern reflex is to begin justice with relations among men. The saints begin it higher. If justice is “to give each his due,” then the first creditor is God, to whom we owe being, life, and salvation. The virtue that renders this due to God, Saint Thomas calls religion, and he makes it the first of the virtues annexed to justice:
“Religion renders to God, as far as possible, the honor that is due to Him; it is the first of the moral virtues [annexed to justice].” — according to Saint Thomas Aquinas, Summa Theologica, II-II, q. 81, a. 6[6]
This is the background to Christ’s word about the coin, which the Fathers read as a lesson in justice: to Caesar what bears his image, but to God what bears His image, that is, the whole human person.
“Render therefore to Caesar the things that are Caesar’s, and to God the things that are God’s.” — Gospel according to Saint Matthew 22:21[7]
Justice toward God is therefore not an extra piety: it is the most fundamental part of virtue. A man scrupulously honest with his fellow men, but who refused God worship and thanksgiving, would, in the eyes of the saints, be an unjust man — an insolvent debtor to his first creditor. That is why biblical wisdom first addresses the call to justice to the powerful, those most tempted to forget themselves before God:
“Love justice, you who govern the earth.” — Book of Wisdom 1:1[8]
“Without Justice, Kingdoms Are But Great Bands of Robbers”
When justice leaves the cities, it is not only laws that fall: it is the very legitimacy of power. Saint Augustine said this in a phrase that has endured through fifteen centuries of political thought. Comparing a kingdom without justice to an organized band of robbers, he writes:
“If justice be taken away, what are kingdoms but great robberies? And what are robberies themselves but little kingdoms?” — Saint Augustine, The City of God, IV, 4[9]
This sentence is not an anarchist cry: it states that justice alone distinguishes authority from theft. Power that does not give each his due has only force behind it, and force without justice is but large-scale brigandage, protected by impunity. The holy kings and holy jurists of the Middle Ages drew from this a concrete demand: to govern is first of all to render justice (see below Saint Louis and Saint Yves).
This public justice has an end that the prophets had already named: not cold order, but peace. Isaiah makes this promise, and tradition has retained it as a motto:
“The work of justice shall be peace, and the effect of justice, quietness and assurance forever.” — Isaiah 32:17[10]
“Mercy and truth are met together; righteousness and peace have kissed each other.” — Psalm 84 (85):11[11]
Justice toward the Poor: A Debt, Not Alms
This is undoubtedly the point where the saints have been most decisive—and most unsettling. For the Church Fathers, aiding the poor is not primarily an optional act of generosity: it is the fulfillment of a debt of justice. The surplus of the rich already belongs, by right, to the indigent.
Saint Basil: “The Bread You Keep Belongs to the Hungry”
Commenting on the parable of the rich fool who tears down his barns to build larger ones (Lk 12:16-21), Saint Basil the Great delivers one of the most famous passages in all of social patristics:
“The bread you keep belongs to the hungry; the cloak you store in your chests belongs to the naked; the shoes rotting in your possession belong to the barefoot; the money you keep buried belongs to the poor. Thus you wrong as many people as you could have helped.” — Saint Basil the Great, Homily “I Will Tear Down My Barns”, § 7[12]
The vocabulary is juridical, not sentimental: belongs, you wrong. For Basil, keeping surplus while another dies is not a lack of heart: it is committing an injustice, almost theft.
Saint Ambrose: “You Do Not Give a Gift, You Return What Is His”
In Milan, Saint Ambrose uses exactly the same language in his treatise Naboth (on the poor Naboth dispossessed of his vineyard). The phrase became so central that it was quoted by Pope Paul VI in the encyclical Populorum progressio:
“You do not give the poor a gift of what belongs to you: you return to him what is his. For what was given in common for the use of all, you have appropriated. The earth was given to all, not to the rich alone.” — Saint Ambrose, De Nabuthe, ch. 12, no. 53[13]
Saint John Chrysostom and Saint Gregory the Great: Paying a Debt of Justice
Two other Doctors seal the doctrine. Saint John Chrysostom, in his homilies on poor Lazarus, even speaks of theft:
“Not sharing one’s goods with the poor is to steal from them and to take away their life. These are not our goods that we hold, but theirs.”
— Saint John Chrysostom, Homilies on Lazarus, 1, 6 (PG 48, 992D)[14]
And Saint Gregory the Great formulates the rule that will be engraved in the Catechism: what we believe we offer by charity, we already owe by justice.
“When we give to the poor what is necessary for them, we do not make a personal generosity; we return to them what is theirs. It is a duty of justice that we fulfill, more than a work of charity.” — Saint Gregory the Great, Pastoral Rule, III, 21, cited by the Catechism of the Catholic Church § 2446[15]
Four voices, one juridical vocabulary—the word “debt” and the verb “to return” recur in each:
| Church Father | Formula on the Rich Man’s Surplus | Vocabulary Used |
|---|---|---|
| Saint Basil the Great | “The bread you keep belongs to the hungry” | belongs, you wrong |
| Saint Ambrose | “You do not give a gift, you return what is his” | reddis — you return |
| Saint John Chrysostom | “Not sharing with the poor is to steal from them” | theft, taking away life |
| Saint Gregory the Great | “We return to them what is theirs” | debt of justice |
The Catechism itself draws the conclusion, without any mitigation: “The demands of justice must be satisfied first, so as not to offer as a gift of charity what is already owed under justice”[16]. The entire social patristic teaching is contained in this reversal: before being generous, be just.
Justice and Mercy: The Saints Refuse to Separate Them
Justice that crushes would be a caricature; mercy that dissolves all law would be another. The saints hold both together. The most cited maxim—traditionally attributed to Saint Thomas Aquinas in his commentary on Saint Matthew—states the exact balance:
“Justice without mercy is cruelty; mercy without justice is the mother of dissolution.” — maxim traditionally attributed to Saint Thomas Aquinas, Super Evangelium Matthaei[17]
The same tension is already present in the prophet Micah, who summarizes all authentic religion in three acts, in which justice and mercy are inseparable:
“He has told you, O man, what is good; and what does the Lord require of you but to do justice, to love mercy, and to walk humbly with your God?” — Micah 6:8[18]
For the saints, justice is therefore never an end closed in on itself: it opens onto mercy as its fulfillment, without dissolving into it. Rendering what is due remains the foundation; but the just man according to God’s heart knows that the final measure is not the code, but love—“mercy triumphs over judgment” (Jas 2:13)[19].
Justice in Action: Three Figures of Righteous Saints
The saints did not merely speak about justice: they embodied it. Three figures sum it up — a silent craftsman, an advocate for the poor, a king beneath an oak tree.
Saint Joseph, “the Just Man”
The Gospel bestows the title of just on only one man, in a single word: Joseph. And it does so at the very moment when his justice must be united with delicacy:
“But her husband Joseph, being a just man and unwilling to put her to shame, resolved to divorce her quietly.” — Gospel according to Saint Matthew 1:19[20]
Joseph’s justice is not cold severity: it seeks to do what is right and refuses to cause harm; it is taught by the angel and obeys immediately. He is the exact model of a justice that hungers for what is right without losing mercy — proof, in a single verse, that the two can coexist in the same heart.
Saint Yves of Kermartin, “Advocate and Not Thief”
In the 13th century, Yves Hélory de Kermartin (c. 1253–1303), priest and ecclesiastical judge in Brittany, became the advocate of the poor: he defended those who could not pay, reconciled litigants, and refused gifts. The people coined a phrase that became a proverb — so rare that it astonishes: an honest man of law.
“Sanctus Ivo erat Brito, advocatus et non latro, res miranda populo.”
“Saint Yves was Breton, advocate and not thief — a marvel to the people.”[21]
Canonized in 1347, Saint Yves is today the patron saint of all legal professions. His life shows what justice is worth when it moves from theory to the courtroom: not merely knowledge of what is right, but a man who gives each their due, even if poor and voiceless.
Saint Louis IX Administering Justice Under the Oak
King Louis IX (1214–1270) left Christian memory with the most concrete image of royal justice. His crusade companion, Jean de Joinville, captured the scene in his Life of Saint Louis: the king himself administering justice outdoors, accessible even to the humblest of his subjects.
“Many times in summer after Mass he would go to sit in the woods of Vincennes, leaning against an oak, and would have us sit around him. And all those who had business came to speak to him, without a bailiff or anyone else stopping them.”
— Jean de Joinville, Life of Saint Louis (c. 1309)[22]
The image has become iconic: justice is not a distant bureaucracy but a personal duty of the powerful, rendered openly, within reach of the poor. Saint Louis enacts Augustine’s sentence: a king is king only insofar as he administers justice; everything else is mere power.
Justice Fulfilled: “Christ, Our Justice”
All these voices converge toward a summit. Human justice, however lofty, remains measured by a greater justice, that of the Kingdom. Christ declares it must surpass the calculative justice of the Law’s specialists:
“For I tell you, unless your righteousness exceeds that of the scribes and Pharisees, you will never enter the kingdom of heaven.”
— Gospel according to Saint Matthew 5:20[23]
And He makes the thirst for this justice a beatitude — proof that it is not a legalistic burden, but a blessed desire that only God can satisfy:
“Blessed are those who hunger and thirst for righteousness, for they shall be satisfied.”
— Gospel according to Saint Matthew 5:6[24]
This justice no man produces alone: he receives it. Saint Paul gives the key: Christ has become our justice. The Christian’s justice is not primarily a moral achievement but a received gift, which then flows forth in right actions.
“And because of him you are in Christ Jesus, who became to us wisdom from God, righteousness and sanctification and redemption.”
— First Letter to the Corinthians 1:30[25]
Giving God All the Glory: Justice in the Divine Will
The spirituality of the Divine Will, transmitted to the Servant of God Luisa Piccarreta (1865–1947), carries this logic to its fulfillment. If justice is “giving each their due,” perfect justice would be to give God all that creation owes Him — glory, love, adoration — without holding anything back. Yet man alone is incapable of this: only Christ’s Fiat — that word by which God creates — rendered to the Father a justice worthy of Him[26]. To live in the Divine Will — not merely doing God’s will like an obedient servant, but living in His Will, as a child lives in his father’s house — is to unite oneself to this Fiat to restore to God, in union with Christ, the justice that creation owes Him and cannot pay by itself[27]. The highest justice thus joins the highest prayer: “Thy will be done.”
This is the saints’ final word on justice: it begins by giving each their due, culminates in giving God His glory, and ends only in love. “But seek first the kingdom of God and his righteousness, and all these things will be added to you” (Mt 6:33)[28] — for justice brought to its fullness bears another name: holiness.
For Further Reading
- [[comment-grandir-dans-la-justice|How to Grow in Justice] — the practical path: the nature of virtue, its types according to Saint Thomas (commutative, distributive, legal), concrete means to foster its growth, and pitfalls to avoid.
- [[dieu-justice-misericorde|God of Justice and Mercy] — the divine attribute: how God’s Justice is united with His Mercy, and not the other way around.
- [[les-erreurs-frequentes-concernant-la-justice|Common Errors Concerning Justice] — misunderstandings to avoid: justice reduced to legalism, vengeance, or the mere assertion of one’s rights.
- [[la-justice-restaurative|Restorative Justice] — the repair of wrongs from a perspective of healing and reconciliation.
- [[que-disent-les-saints-sur-laumone|What the Saints Say About Almsgiving] — the voice of the saints on giving to the poor, a direct extension of patristic justice toward the indigent.
- [[que-disent-les-saints-sur-la-temperance|What the Saints Say About Temperance], [[que-disent-les-saints-sur-la-prudence|What the Saints Say About Prudence], and [[que-disent-les-saints-sur-la-force|What the Saints Say About Fortitude] — the voice of the saints on the other three cardinal virtues.
Notes and References
Saint Thomas Aquinas (1225–1274), Summa Theologica, II-II, q. 58, a. 1, adopting the definition of the Roman jurist Ulpian (Digest I, 1, 10): « iustitia est constans et perpetua voluntas ius suum unicuique tribuens » — “justice is the constant and perpetual will to render to each his due.” Standard edition: Summa Theologiae, Éditions du Cerf.
1Catechism of the Catholic Church, § 1807. Canonical definition of justice as a cardinal virtue: “the constant and firm will to give God and neighbor what is their due.” Official French edition, Mame/Plon, 1992.
2Saint Thomas Aquinas, Summa Theologica, II-II, q. 58, a. 11, resp.: « proprius actus iustitiae nihil est aliud quam reddere unicuique quod suum est » — “the proper act of justice is nothing other than to render to each what is his own.”
3Saint Thomas Aquinas, Summa Theologica, II-II, q. 58, a. 12: justice is the most excellent of the moral virtues for two reasons — it resides in the will (rational appetite, a faculty superior to sensibility) and its object is the good of others, thus a more universal good than one’s own good. (Summary formulation based on the Thomistic text.)
4Saint Augustine (354–430), De moribus Ecclesiae catholicae, I, 15, 25 (Patrologia Latina, Migne, vol. 32): defining the four cardinal virtues as forms of love of God, he writes that « iustitia est amor Deo tantum serviens, et ob hoc bene imperans ceteris quae homini subiecta sunt » — “justice is love serving only God, and therefore rightly governing all that is subject to man.” Formula taken up word for word by Saint Thomas Aquinas, Summa Theologica, II-II, q. 57, a. 1, obj. 3; Latin text on augustinus.it and newadvent.org (NPNF); French trans. Poujoulat-Raulx, Œuvres complètes de saint Augustin.
5Saint Thomas Aquinas, Summa Theologica, II-II, q. 81, a. 6: religion is the first of the moral virtues annexed to justice because it renders to God — the principle and end of all — the worship and honor due to Him; cf. CCC §§ 2095–2096. (Citation paraphrased from the Thomistic text.)
6Gospel according to Saint Matthew 22:21, official liturgical translation (AELF). Christ’s response on paying tribute to Caesar; read by the Fathers as a lesson in justice: render to each, and first to God, what is due.
7Book of Wisdom 1:1, official liturgical translation (AELF); Vulgate: « Diligite iustitiam qui iudicatis terram ». Opening verse of the book, addressed to rulers.
8Saint Augustine, The City of God (De civitate Dei), IV, 4: « Remota itaque iustitia quid sunt regna nisi magna latrocinia ? quia et latrocinia quid sunt nisi parva regna ? ». The passage is introduced by the anecdote of the captured pirate replying to Alexander the Great. Full text available at newadvent.org (CHURCH FATHERS) and CCEL (NPNF, vol. 2).
9Isaiah 32:17, official liturgical translation (AELF); Vulgate: « et erit opus iustitiae pax ». Peace presented as the proper fruit of justice.
10Psalm 84 (85):11, official liturgical translation (AELF): “Love and truth meet; justice and peace embrace.” Numbering 84 (Greek/liturgical) = 85 (Hebrew).
11Saint Basil the Great (c. 330–379), Homily on Luke 12:18 “I will destroy my barns” (In illud Lucae: Destruam horrea mea), § 7; Greek text in Patrologia Graeca (Migne), vol. 31, col. 277. This phrase is one of the major patristic sources for the doctrine of the universal destination of goods (cf. CCC §§ 2402–2406, 2446).
12Saint Ambrose (c. 340–397), De Nabuthe (On Naboth), ch. 12, no. 53: « Non de tuo largiris pauperi, sed de suo reddis » — “It is not from your own goods that you give to the poor; you restore to them what is theirs.” Quoted by Pope Paul VI, encyclical Populorum progressio (1967), no. 23.
13Saint John Chrysostom (c. 349–407), Homilies on the Poor Lazarus (De Lazaro), 1, 6 (PG 48, 992D): “Not sharing one’s goods with the poor is to steal from them and take away their life. These are not our goods that we hold, but theirs.” Quoted by the Catechism of the Catholic Church § 2446.
14Saint Gregory the Great (c. 540–604), Pastoral Rule (Regula pastoralis), III, 21, cited by the Catechism of the Catholic Church § 2446: “When we give the needy what is necessary, we do not make a personal gift but restore to them what is theirs. More than performing a work of mercy, we discharge a debt of justice.”
15Catechism of the Catholic Church, § 2446, citing Saint John Chrysostom and Saint Gregory the Great: “The demands of justice must be satisfied first, so as not to offer as a gift of charity what is already owed by justice.”
16Traditional maxim attributed to Saint Thomas Aquinas, commentary on the Gospel of Saint Matthew (Super Evangelium Matthaei, ch. 5): « Iustitia sine misericordia crudelitas est ; misericordia sine iustitia, mater est dissolutionis » — “justice without mercy is cruelty; mercy without justice is the mother of dissolution.” The exact attribution is debated; the balance of the two virtues is in any case a classic of moral theology.
17Micah 6:8, official liturgical translation (AELF). Prophetic summary of authentic religion: to do justice, to love mercy, and to walk humbly with God.
18Epistle of Saint James 2:13, official liturgical translation (AELF): “For judgment is without mercy to one who has shown no mercy; mercy triumphs over judgment.”
19Gospel according to Saint Matthew 1:19, official liturgical translation (AELF). Joseph “a just man” (vir iustus): his justice is both fidelity to the law and refusal to harm, open to God’s will.
20Saint Yves Hélory of Kermartin (c. 1253–1303), priest and official (ecclesiastical judge) of the diocese of Tréguier, canonized May 19, 1347 by Pope Clement VI; patron saint of lawyers and advocates. The popular distich “Sanctus Ivo erat Brito, advocatus et non latro, res miranda populo” is traditionally associated with him. Source: Breton hagiographic tradition; cf. notice of the Paris Bar Museum.
21Jean de Joinville (c. 1224–1317), Life of Saint Louis (written c. 1305–1309), § 59: King Louis IX administering justice under the oak of Vincennes. Modern French translation from the Old French text; standard edition: Jean de Joinville, Vie de saint Louis, ed. Jacques Monfrin, Classiques Garnier / Le Livre de Poche.
22Gospel according to Saint Matthew 5:20, official liturgical translation (AELF). The justice of the Kingdom must “surpass” the merely external justice of the scribes and Pharisees.
23Gospel according to Saint Matthew 5:6, official liturgical translation (AELF). Fourth Beatitude (Mt 5:3–12); “justice” here denotes both moral uprightness and the fulfillment of God’s will.
24First Letter to the Corinthians 1:30, official liturgical translation (AELF). Christ “became for us justice”: the Christian’s justice is rooted in the justice received from Christ, not merely in moral performance.
25Jesus to the Servant of God Luisa Piccarreta (1865–1947), The Book of Heaven, volume 6, dictation of September 26, 1904: speaking of His Passion, Christ says that He drew upon “my Intelligence, my Memory and my Will, as well as these threefold sufferings, to render complete the Glory owed to the Father and for the good of creatures” — “to give God all the Glory that it [the creature] owes Him.” French edition: GE – La Volonté Divine – Lumen Luminis (for private use), pp. 69–70.
26Jesus to the Servant of God Luisa Piccarreta (1865–1947), The Book of Heaven, volume 12, dictation of December 6, 1919: Luisa prays “in your Will and in the name of the whole human family [...] I want to love You and make reparation in the name of all, from the first man to the last”; Jesus answers her: “Finding in you the love that these souls owe Me, I have poured into you the graces I had intended for them.” French edition: GE – La Volonté Divine – Lumen Luminis (for private use), p. 155.
27Gospel according to Saint Matthew 6:33, official liturgical translation (AELF). “Seek first the kingdom of God and his justice, and all these things will be given you besides.”
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