Topic 34: The Ninth and Tenth Commandments

The ninth and tenth commandments refer to internal acts corresponding to sins against the sixth and seventh commandments. Internal sins can deform the conscience. The struggle against internal sins is part of the Christian’s endeavour to love with all one’s heart, mind and strength. Purity of heart means having a holy way of feeling.

“Thou shalt not covet thy neighbour’s wife, nor desire thy neighbour’s house, nor his land, nor his manservant, nor his maidservant, nor his ox, nor his ass, nor any thing that is thy neighbour’s” (Deut 5:21).

“But I say to you that everyone who looks at a woman lustfully has already committed adultery with her in his heart” (Mt 5:28).

Sanctifying the inner world

Jesus’ words when answering a question about what is most important in the Law show that the moral life is not just a series of external acts, but something much deeper: “You shall love the Lord your God with all your heart and with all your soul and with all your spirit and with all your strength” (Mk 12:0). Holiness, which is always a gift of God, does not consist fundamentally in a life without serious sins, but in a life filled with God’s love; this love requires an inner order and harmony that it is impossible for us to attain without grace, but that can be perceived in holy people. At the same time, correspondence to this gift of God is within our reach; so many of our brothers and sisters in the faith have known how to make this grace bear fruit through their personal effort: “Master, you delivered to me five talents; here I have made five talents more” (Mt 25:20).

This inner order and harmony is what is known as “purity of heart,” which is praised by Jesus in the Sermon on the Mount, and which also enables us to open our heart to our neighbour: “By this path we enter a relationship with our neighbour which, springing from the love that God shows us in Christ, is a call to the beauty of fidelity, generosity and authenticity. But to live in this way — that is, in the beauty of fidelity, generosity and authenticity — we need a new heart, inhabited by the Holy Spirit . . . the gift of new desires (cf. Rom 8:6). To desire according to the Spirit, to desire with the rhythm of the Spirt, to desire with the music of the Spirit . . . This is what the Decalogue is for us Christians: to contemplate Christ in order to open ourselves up to receive his heart, to receive his will, to receive his Holy Spirit.”[1]

Affection for people and material goods is good in itself, but it requires an order that takes into account the person’s integral good, which for Christians entails love for God that involves the whole person: intellect, heart and the rest of one’s faculties. Material goods, while indispensable means, are not capable of fulfilling the aspiration for the infinite in the human heart, which is made for God and which is not satisfied with material well-being. This well-being, when it is not integrated into life according to the Holy Spirit, often dulls the intellect and heart and makes it difficult to truly love others and to recognise their needs.

Internal sins

These two commandments refer to internal acts that are sins against the sixth and seventh commandments, which moral tradition classifies as internal sins. From a positive point of view, they prescribe living purity (the ninth) and detachment from material goods (the tenth) in our thoughts and desires, living in accord with Christ’s words: “Blessed are the pure in heart, for they shall see God” and “Blessed are the poor in spirit, for theirs is the kingdom of heaven” (Mt 5:3.8).

The first point to clarify here is whether it makes sense to speak of “internal” sins. In other words, why should an act of the intellect and will that is not expressed in an external action be viewed as morally reprehensible?

The answer is not obvious since the lists of sins found in the New Testament appear to be mainly external acts: adultery, fornication, homicide, idolatry, sorcery, quarrels, giving in to anger, etc. And yet, in the same catalogue of sins we also find certain internal acts cited as sins: envy, evil desires, avarice.[2]

Jesus himself says that “evil thoughts, murder, adultery, fornication, theft, false witness, slander” (Mt 15:19) come from man’s heart. And referring specifically to chastity He teaches “that everyone who looks at a woman lustfully has already committed adultery with her in his heart” (Mt 5:28). These texts are important for our understanding of morality since they stress that the source of human actions, and therefore of the good or evil in a person, is found in the desires of the heart, in what the person wants and chooses. The evil of murder, adultery, theft is not primarily in the physical reality of the action, or in its consequences (although these are an important part of it), but in the will, in the heart of the murderer, the adulterer, the thief, who in choosing that particular action is deciding on an orientation opposed to love for one’s neighbor, and therefore also to love for God.

The will always seeks a good, but at times what appears good is something that is not rationally ordered to one’s overall good. The thief seeks something that he considers good, but the fact that the object belongs to another person makes the choice to obtain it something that cannot contribute to his own good as a person, that is, to the purpose of his life. In this sense, an exterior action is not required to decide if the will is heading in a good or bad direction. Anyone who decides to steal an object, even if something unforeseen keeps him from doing so, has “acted” badly. He has carried out an internal act of the will against the virtue of justice.

The goodness or wickedness of a person is rooted in the will, and so, strictly speaking, we should use these categories to refer to desires (what we want, approve), and not to thoughts. To speak of the intellect we use other categories such as true or false. When the ninth commandment forbids “impure thoughts” it is not referring to images or to the thoughts in themselves, but to the movement of the will which accepts the disordered pleasure provoked by a certain image (internal or external).[3]

Internal sins have traditionally been divided into:

– evil thoughts: these consist in imagining a sinful act without the intention to carry it out. It is a mortal sin if it involves a serious matter and if taking pleasure in it is sought or consented to;

– evil desire: an internal desire for a sinful action that the person willingly accepts. This is not the same as the intention to carry it out (which always implies the actual desire to do so), although in many cases the person would carry it out if not for restraining reasons (such as the consequences of the action, difficulty in carrying it out, etc.);

– sinful complacence: that is, deliberately taking pleasure in an evil action carried out by oneself or by others. This renews the sin in the soul.

In themselves, internal sins are usually less serious than the corresponding external sins since the external action generally manifests a more deliberate willfulness. Nevertheless they are in fact very harmful, above all for persons seeking to grow in friendship with God, since:

they are committed more easily, since only the consent of the will is needed, and temptations can be more frequent;

one pays less attention to them, since at times out of ignorance and at times out of a certain complicity with the passions, one does not want to recognize them as sins, at least venial ones, if there is imperfect consent.

Internal sins can deform the conscience, as when one accepts an internal venial sin as a matter of habit or with a certain frequency, although one seeks to avoid mortal sin. This deformation can give rise to manifestations of irritability, lacks of charity, critical spirit, resigning oneself to having frequent temptations without struggling tenaciously against them, etc.[4] In some cases, this can lead to not wanting to recognize internal sins, hiding them with unreasonable excuses, and thus confusing one’s conscience even more. As a result, self-love easily increases, worries arise, humility and sincere contrition become more difficult and lukewarmness can easily result.

The struggle against inner sins, which builds up a moral refinement and harmony within the person, has nothing to do with scruples, which are a hypertrophy of inner sensitivity and can become a real psychic disorder.

The fight against inner sins is part of the Christian endeavour to love with one’s whole heart, mind and strength. In this area we are helped by:

– frequenting the sacraments, which give us grace or increase it, and heal us of our daily mistakes;

– prayer, mortification and work, seeking God sincerely;

– humility, which enables us to recognize our wretchedness without getting discouraged by our mistakes, and trust in God, knowing that He is always ready to forgive us;

– being sincere with God, with ourselves and in spiritual direction, taking special care of the examination of conscience.

Purifying the heart

The ninth and tenth commandments deal with the internal roots of sins against chastity and justice, and in a wider sense, of any sin.[5] In a positive sense, these commandments invite us to act with right intention, with a pure heart. This is why they are of great importance, for they do not stop at the external consideration of actions, but consider the source from which these actions stem.

These internal operations are fundamental in the moral life of Christians, where the gifts of the Holy Spirit and the infused virtues are received in accord with a person’s dispositions. Of special importance here are the moral virtues, which are dispositions of the will and of the sense appetites to do good. By giving importance to these factors, we can overcome a certain caricature of the moral life as merely a struggle to avoid sin, and discover the immensely positive panorama of the effort to grow in virtue and purify our heart.

These commandments refer more specifically to internal sins against the virtues of chastity and justice, which are clearly reflected in the text of Sacred Scripture which speaks of “three kinds of covetousness or concupiscence: lust of the flesh, lust of the eyes, and pride of life (1 Jn 2:16)” (Catechism, 2514).

Every man and woman discovers within some disordered tendencies, which moral tradition has called concupiscence. The Catechism explains this when speaking of “the rebellion of the ‘flesh’ against the ‘spirit.’ Concupiscence stems from the disobedience of the first sin” (Catechism, 2515). After original sin no one is exempt from concupiscence, with the exception of our Lord Jesus Christ and our Lady.

Although concupiscence in itself is not sinful, it inclines us to sin and gives rise to sin when it is not subject to reason enlightened by faith, with the help of grace. If one overlooks the reality of concupiscence, it is easy to think that all the tendencies we feel are “natural” and that there is nothing wrong in being guided by them. Many people realize that this is false when they consider the impulse to violence, seeing clearly that we must not be led by this impulse but must control it. In the area of chastity, however, it is not so easy to recognise that “natural” stimuli are often inappropriate. The ninth commandment helps us understand that this is not true, since concupiscence has wounded our nature, and what we feel as natural is frequently the consequence of sin, and needs to be controlled. The same could be said about the excessive desire for riches, or covetousness, prohibited by the tenth commandment.

It is important that we be aware of this disorder caused in us by original sin and by our personal sins, since this knowledge:

incites us to pray: only God can undo original sin, the source of concupiscence; likewise only with his help will we succeed in overcoming this disordered tendency. God’s grace heals the wounds of sin in our nature and raises us to the supernatural order;

teaches us to love all creatures, since everything coming from God’s hands was created good; it is our disordered desires that twist God’s creation.

The struggle for purity and freedom of heart

Purity of heart means having a holy way of feeling. With God’s help and our own struggle we can acquire an ever greater “purity of heart”: purity in our thoughts and desires. This cleansing or purity of heart brings with it an increased freedom of our heart to love.

As far as the ninth commandment is concerned, Christians obtain this purity through God’s grace and through the virtue and gift of chastity, through purity of intention and sight, and through prayer.[6]

Purity of sight is not just refusing to look at something clearly unsuitable. It also requires purifying the use of our external senses, leading us to look at the world and at other men and women with supernatural vision, with Christ’s eyes. This entails a positive struggle that enables us to discover the real beauty of all created reality and, in a special way, the beauty of those who have been formed in the image and likeness of God.[7]

“Purity requires modesty, an integral part of temperance. Modesty protects the intimate center of the person. It means refusing to unveil what should remain hidden. It is ordered to chastity to whose sensitivity it bears witness. It guides how one looks at others and behaves toward them in conformity with the dignity of persons and their solidarity” (Catechism, 2521).

As far as material goods are concerned, today’s society encourages consumerism and self-assertion so powerfully that it even endangers the stability of the family. Many people realise too late that they have focused their lives on their profession, on earning money and social standing, and have neglected other more important facets of their life: their relationship with God and their family.

The exaggerated importance given today to material well-being above many other values is not a sign of human progress; it is a diminishment and debasement of the human person, whose dignity lies in being a spiritual creature called to eternal life as a child of God (cf. Lk 12:19-20).

“The tenth commandment requires that envy be banished from the human heart” (Catechism, 2538). Envy is a capital sin. It “referes to the sadness at the sight of another’s goods” (Catechism, 2539). Envy can give rise to many other sins: hatred, calumny, detraction, disobedience, etc. Envy is opposed to charity. To fight against it we need to live the virtue of benevolence, which leads us to desire the good of others as a manifestation of our love for them. The virtue of humility also helps us in this struggle, since envy often stems from pride (Cf. Catechism, 2540).

To be able to love with all one’s heart and strength requires interior order, which comes with grace and the virtues. This is not simply a matter of continence, which at most avoids the most serious sins, but rather means attaining the peace-filled harmony that holy people have.

Basic bibliography

Catechism of the Catholic Church, 2514-2557.

Recommended reading

Saint Josemaría, Homily "For they shall see God" in Friends of God, 175-189; Homily "Detachment" in Friends of God, 110-126.

[1] Pope Francis, General Audience, 28 November 2018.

[2] Cf. Gal 5:19-21; Rom 1:29-31; Col 3:5. After making an appeal to shun fornication, Saint Paul writes: “that each one of you know how to control his own body in holiness and honor, not in the passion of lust like heathen who do not know God . . . For God has not called us for uncleanness, but in holiness” (1 Thess 4:4-7). In doing so, he emphasizes the importance of the feelings, which lie at the root of our actions, and the need to purify them for the sake of attaining sanctity.

[3] Thus one needs to keep clear the difference between “feeling” and “consenting” in reference to a particular passion or movement of the senses. Only when there is consent of the will is it a question of sin (if the matter is sinful).

[4] “You play around with temptations, you put yourself in danger, you fool around with your sight and with your imagination, you chat about... stupidities. And then you are anxious that doubts, scruples, confusion, sadness and discouragement might assail you. You must admit that you are not very consistent” (Saint Josemaria, Furrow , 132).

[5] ”The tenth commandment concerns the intentions of the heart; with the ninth, it summarizes all the precepts of the Law” (Catechism, 2534).

[6] ”With God’s grace he will prevail: by the virtue and gift of chastity, for chastity lets us love with upright and undivided heart; by purity of intention which consists in seeking the true end of man: with simplicity of vision, the baptized person seeks to find and to fulfill God’s will in everything; (cf. Rom 12:2; Col 1:10); by purity of vision, external and internal; by discipline of feelings and imagination; by refusing all complicity in impure thoughts that incline us to turn aside from the path of God’s commandments: ‘Appearance arouses yearning in fools’ (Wis 15:5); by prayer” (Catechism, 2520).

[7] ”The eyes! Through them many iniquities enter the soul. — What experiences like David’s! — If you guard your sight you have assured the guard of your heart” (Saint Josemaría, The Way, 183). “Dear Lord, I find beauty and charm in everything I see! I will guard my sight at every moment, for the sake of Love” (Saint Josemaría, The Forge, 415).