We often hear about the sin of lust, but can you tell me exactly what it is? Is it the same as impure thoughts? Is it a mortal sin?
The Catechism of the Catholic Church says that “Lust is disordered desire for or inordinate enjoyment of sexual pleasure. Sexual pleasure is morally disordered when sought for itself, isolated from its procreative and unitive purposes” (CCC 2351).
As this point implies, there can be a legitimate desire for and enjoyment of sexual pleasure.
This is the case when their object is the act of intimacy within marriage.
In this act, the procreative aspect of intimacy, that is its openness to life, and the unitive aspect, the one-flesh union of husband and wife, are respected.
Thus, when husband and wife desire to give themselves to one another in an act of love open to life, and they desire the pleasure that accompanies this act, they are acting honourably and there is no suggestion of the sin of lust.
The same could be said of engaged couples who desire the act of intimacy they will have when they are married.
As regards the pleasure experienced in the act, Pope Pius XII said: “The Creator himself … established that in the [generative] function, spouses should experience pleasure and enjoyment of body and spirit.
Therefore, the spouses do nothing evil in seeking this pleasure and enjoyment.
They accept what the Creator has intended for them. At the same time, spouses should know how to keep themselves within the limits of just moderation” (Address, 9 October 1951).
By the expression “within the limits of just moderation”, the Pope is implying that there could be even for married couples a possible sin of lust in their expression of love if they sought the pleasure merely for pleasure’s sake or they sought to maximise it in a disordered way.
As the Catechism puts it, “The acts in marriage by which the intimate and chaste union of the spouses takes place are noble and honourable; the truly human performance of these acts fosters the self-giving they signify and enriches the spouses in joy and gratitude” (CCC 2362).
Lust, then, is the desire for sexual pleasure outside the marriage act, or in a marriage act not open to life. It is one of the seven capital sins, or capital vices, mentioned by St Gregory the Great: pride, avarice, envy, wrath, lust, gluttony and sloth” (cf. CCC 1866).
These sins are called capital, from the Latin word for head, because they are the heads or principles which lead to other vices and sins.
Lust is very much related to the ninth commandment: You shall not covet your neighbour’s wife (cf. Ex 20:17).
Our Lord spoke strongly against it: “You have heard that it was said, ‘You shall not commit adultery.’
But I say to you that every one who looks at a woman lustfully has already committed adultery with her in his heart” (Mt 5:27-28).
Looking at a woman lustfully in this context means desiring to have sexual relations with a woman other than one’s wife.
The very desire, if it is more than just a passing thought, is already the sin of adultery in the heart, and it would be a mortal sin.
Pope St John Paul II, in one of his Theology of the Body addresses, spoke about how lust reduces the natural attraction of men for women, and vice versa, to an attraction merely for the body: “When compared with the original mutual attraction of masculinity and femininity, lust represents a reduction.
In stating this, we have in mind an intentional reduction, almost a restriction or closing down of the horizon of mind and heart.
It is one thing to be conscious that the value of sex is a part of all the rich storehouse of values with which the female appears to the man.
It is another to ‘reduce’ all the personal riches of femininity to that single value, that is, of sex, as a suitable object for the gratification of sexuality itself” (Address, 17 Sept. 1980).
St Thomas Aquinas says that the consequences of lust are “blindness of mind, thoughtlessness, inconstancy, rashness, self-love, hatred of God, love of this world and abhorrence or despair of a future world” (STh II-IIae, q. 153, art. 5).
We see here how damaging lust can be.
Thus lust is a particularly serious form of impure thought and it can certainly be a mortal sin.
It debases man and how he looks upon women.
We are called to something higher, to holiness, to purity of heart: “Blessed are the pure in heart, for they shall see God” (Mt 5:8).