Pope St. John Paul II said this about purity, "If purity disposes man to 'keep his own body with holiness and reverence,' as we read in 1 Thessalonians 4:3-5, piety, as the gift of the Holy Spirit, seems to serve purity in a particular way by making the human subject sensitive to the dignity that belongs to the human body in virtue of the mystery of creation and redemption. …” (Man and Woman He Created Them: A Theology of the Body 352-353).
So then, purity is keeping one’s “own body with holiness and reverence”. But how to do that and why? Again, it is Pope St. John Paul II who states, “The analysis of purity is an indispensable completion of the words Christ spoke in the Sermon on the Mount… When explaining the correct meaning of the commandment, ‘You shall not commit adultery,’ Christ appealed to the interior man. At the same time, he specified the fundamental dimension of purity that marks the relations between man and woman both in marriage and outside it. The words, ‘But I say to you that everyone who looks at a woman lustfully has already committed adultery with her in his heart’ (Mt 5:27-28), express what is opposed to purity. At the same time, these words demand the purity which, in the Sermon on the Mount, is included in the list of the beatitudes: ‘Blessed are the pure in heart, for they shall see God’ (Mt 5:8). In this way Christ appealed to the human heart. He called upon it and did not accuse it…”
Purity then, is the virtue that will lead us to “see God”. This is why there are many saints who stress the necessity of purity and at the same time, praise it for its beauty and virtue. Let us follow their example, as they will show us how to be “pure of heart”:
“Every virtue in your soul is a precious ornament which makes you dear to God and to man. But holy purity, the queen of virtues, the angelic virtue, is a jewel so precious that those who possess it become like the angels of God in Heaven, even though clothed in mortal flesh. “
Blessed Mother Theresa:
"To be pure, to remain pure, can only come at a price. This price is knowing God and loving Him enough to do His will. He will always give us the strength we need to keep purity as something beautiful for Him.”
St. John of the Cross:
"God desires the least degree of purity of conscience in you more than all the works you can perform.”
"Deep within yourself listen to your conscience which calls you to be pure. A home is not warmed by the fire of pleasure, which burns quickly like a pile of weed grass. Passing encounters are only a caricature of love. They injure hearts and mock God’s plan."
"Devotion to the Blessed Sacrament and devotion to the Blessed Mother are not simply the best way, but in fact the only way to keep purity. At the age of 20, nothing but Communion can keep one's heart pure. Chastity is not possible without the Eucharist.”
I would like to finish with these words of the Blessed Mother herself when she appeared to a privileged soul, Sr. Mildred Mary Neuzil, right here in the United States in 1956. She revealed herself under the title of Our Lady of America, ”My child, I entrust you with this message that you must make known to my children in America. I wish it to be the country dedicated to my purity. The wonders I will work will be the wonders of the soul. They must have faith and believe firmly in my love for them. I desire that they be the children of my Pure Heart. I desire, through my children in America, to further the cause of faith and purity among peoples and nations. Let them come with confidence and simplicity, and I, their Mother, will teach them to become pure like to my Heart that their own hearts may be more pleasing to the Heart of my Son.” v