At the beginning of Christ's words in the Sermon on the Mount, he interprets God's plan to restore creation to the purity of its origin and set all man's loves in order. "You have heard 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)
In order to enter a communion with divine life, our affections and emotions need to be redeemed through grace and sound teaching, and so the Lord teaches us here the virtue of temperance. What is temperance? St. Augustine says, "The function of temperance is to control and quell the desires which draw us to the things which withdraw us from the laws of God and from the fruit of his goodness..." Temperance is a virtue of moderation. It does not mean emptiness, withdrawing from others or from the beauty of creation, but enjoying in moderation the good things which God created for us. We allow the life, power and grace of Christ to transform us completely in order to enter a new and beautiful life.
Blessed Pope John Paul II once commented on the writings of St. Augustine, reminding us that the saint invites us to love beauty. It is not only the beauty of bodies, which can easily make one forget the beauty of the spirit, nor only the beauty of art, but the interior beauty of virtue. Christ implanted the gift of communion of grace with the Trinity deep within each human heart. This divine life springs out of the full manifestation of the beauty of marriage and the beauty of consecrated life and the beauty of single life lived chastely for the sake of the Kingdom.