By the ninth commandment we are commanded to be pure in thought and desire.

Blessed are the clean of heart, for they shall see God.  (Matthew 5:8)

Saint Elizabeth of Portugal

Mere thoughts about impure things are not always sinful in themselves, but such thoughts are dangerous.

Thoughts about impure things become sinful when a person thinks of an unchaste act and deliberately takes pleasure in so thinking, or when unchaste desire or passion is aroused and consent is given to it.

The ninth commandment forbids all thoughts and desires contrary to chastity.

You shall not covet your neighbor's horse; you shall not covet your neighbor's wife, or his man servant, or his maid servant, or his ox, or his ass, or anything that is your neighbor's.

Everyone who looks at  a woman lustfully has already committed adultery with her in his heart. (MT 5:28)

Human Desires

St. John states that there are three kinds of concupiscience or covetousness (intense forms of human desire) that one must constantly fight in order to save his or her soul.  They are lust of the flesh, lust of the eyes and pride of life.

Becasue of the results of original sin, there is a constant struggle between the "spirit" and the flesh".  On'es place in eternity depends on the results of this struggle.

The Struggle

As stated in our "Catechism of the Catholic Church" the heart is the seat of moral personality.  Out of the heart comes all the evils of this world, thoughts, adultery, fornication, and murder.

Practicing Temperance

The struggle against all carnal thoughts and actions entails purifying the heart and practicing temperance.

Remain simple and innocent, and you will be like little children who do not know the evil that destroys man's life.

Christ was very specific when he stated that you must become like these little ones to gain the kingdom of heaven.

Pure Heart

According to the sixth beatitude, "Blessed are the pure in heart, for they shall see God.  And those with true purety of heart meet the demands of God's holiness in three areas:

1. Charisty
2. Chastity (the avoidance of all sexual impurities)
3. Love of the truth of our faith

Those that reach this level are promised that they will see God face-to-face and be like Him.

Battle for Purity

This is a constant battle and never ends the struggle against the flesh and disordered.  Desires will always be with you, but with God's loving grace, and the graces He gives through frequent confessions, you will prevail.

Summary (From the Catechism of the Catholic Church)

A.  Everyone who looks at a woman lustfully has already committed adultery with her in his heart. (Mt 5:28)

The ninth commandment warns against lust or carnal cupiscence.

The struggle against carnal lust involves purifying the heart and practicing temperance.

Purity of heart will enable us to see God.  It enables us, even now, to see things according to God's plan.

Purification of the heart demands prayer, the practice of chastity, purity of intention and of vision.

Purity of heart requires the modesty which is patience, decency and discretion.  Modesty protects the intimate center of the person.

B.  The sixth commandment says "Do not commit adultery".  The ninth commandment says, "Don't even think about it".

Everyone is plagued with the temptations of evil thoughts.  The best way to control and to destroy these temptations is to say a concentrated Hail Mary.  Sometimes just one is sufficient.  Ask our Blessed Mother for her help in this constant struggle and she will always answer these prayers.

Another important method in controlling these thoughts is to eliminate all sources of pornography.

Drive all pornography from your minds, keep it from our homes and avoid seeing it on TV, Web sites and in the movies.  Magazines and books are just as dangerous.  These are the tools that can create uncontrollable emotions, which can be the start of a very unhappy life.  For now do everything you can to avoid these temptations.  This will give you an inner strength you didn't know you possessed.