St. Francis De Sales

“Frequent not the company of immodest persons, especially if they be also impudent, as is generally the case; …these corrupted souls and infected hearts scarcely speak to any, either of the same or a different sex, without causing them to fall in some degree from purity; they have poison in their eyes and in their breath, like basilisks. On the contrary, keep company with the chaste and virtuous; often meditate upon and read holy things; for the word of God is chaste, and makes those also chaste that delight in it.”

—St. Francis de Sales, Introduction to a Devout Life, Part Third, Chapter XIII.