St. Augustine of Hippo (354-430) in Book Three of his treatise De doctrina Christiana (On Christian Doctrine) distinguishes between charity and lust: “I mean by charity that affection of the mind which aims at the enjoyment of God for His own sake, and the enjoyment of one’s self and one’s neighbor in subordination to God; by lust I mean that affection of the mind which aims at enjoying one’s self and one’s neighbor, and other corporeal things, without reference to God.”
According to this definition, he can assert that “Scripture enjoins nothing except charity, and condemns nothing except lust, and in that way fashions the lives of men.” Furthermore, “Scripture asserts nothing but the Catholic faith, in regard to things past, future, and present. It is a narrative of the past, a prophecy of the future, and a description of the present. But all these tend to nourish and strengthen charity, and to overcome and root out lust.”
He then shows how lust leads to vice and crime: “What lust, when unsubdued, does towards corrupting one’s own soul and body, is called vice; but what it does to injure another is called crime. And these are the two classes into which all sins may be divided. But the vices come first; for when these have exhausted the soul, and reduced it to a kind of poverty, it easily slides into crimes, in order to remove hindrances to, or to find assistance in, its vices.”
He shows how charity conduces to prudence and benevolence: “In the same way, what charity does with a view to one’s own advantage is prudence; but what it does with a view to a neighbor’s advantage is called benevolence. And here prudence comes first; because no one can confer an advantage on another which he does not himself possess.”
St. Augustine concludes: “Now in proportion as the dominion of lust is pulled down, in the same proportion is that of charity built up.” (III, 10)
Quotations from A Select Library of the Nicene and Post-Nicene Fathers of the Christian Church, Vol. II, ed. Philip Schaff (Edinburgh: T&T Clark, 1886).