Thanks to Jason Evert for permission to use the quotes on purity from www.pureloveclub.com.   
 
"Only the chaste man and the chaste woman are capable of true love."
- Pope John Paul II

"Chastity is a difficult, long term matter; one must wait patiently for it to bear fruit, for the happiness of loving kindness which it must bring. But at the same time, chastity is the sure way to happiness."
- Pope John Paul II

"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 withered grass. Passing encounters are only a caricature of love; they injure hearts and mock God's plan."
- Pope John Paul II

"[God] has assigned as a duty to every man the dignity of every woman."
- Pope John Paul II

"To be pure, to remain pure, can only come at a price, the price of knowing God and loving him enough to do his will. He will always give us the strength we need to keep purity as something as beautiful for him."
- Blessed Mother Teresa

"Holy Purity is granted by God when it is asked for with humility."
- St. Josemaria Escriva

"'Purity?' they ask. And they smile. They are the ones who go on to marriage with worn-out bodies and disillusioned souls."
- St. Josemaria Escriva

"By Lust I mean that affection of the mind that aims at the enjoyment of one's self and one's neighbor without reference to God."
- St. Augustine

"Lust indulged became habit, and habit unresisted became necessity."
- St. Augustine

"There is need for a crusade of manliness and purity to counteract and nullify the savage work of those who think man is a beast. And that crusade is your work."
- St. Josemaria Escriva

"Many live like angels in the middle of the world. You, … why not you?"
- St. Josemaria Escriva

"When you decide firmly to lead a clean life, chastity will not be a burden on you: it will be a crown of triumph."
- St. Josemaria Escriva

"Don't be such as coward as to be 'brave.' Flee!"
- St. Josemaria Escriva

"When you have sought the company of a sensual satisfaction, what loneliness afterward!"
- St. Josemaria Escriva

"To defend his purity, Saint Francis of Assisi rolled in the snow, Saint Benedict threw himself into a thornbush, Saint Bernard plunged into an icy pond . . . You . . . what have you done?"
- St. Josemaria Escriva

"Don't say, 'That's the way I am-its my character.' It's your lack of character. Esto vir!-Be a man!"
- St. Josemaria Escriva

"Purity is the fruit of prayer."
- Blessed Mother Teresa

"Purity prepares the soul for love, and love confirms the soul in purity."
- St. John Henry Cardinal Newman

"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."
- St. John Bosco

"As soon as you willfully allow a dialogue with temptation to begin, the soul is robbed of peace, just as consent to impurity destroys grace."
- St. Josemaria Escriva

"Temptation is necessary to make us realize that we are nothing in ourselves."
- St. Josemaria Escriva

"More souls go to hell because of sins of the flesh than for any other reason."
- Our Lady of Fatima