Nearly everyone who has written about the spiritual life has had in mind those who live apart from the world, or at least the devotion they advocate would lead to such retirement. My intention is to write for those who have to live in the world and who, according to their state, to all outward appearances have to lead an ordinary life; and who, often enough, will not think of undertaking a devout life, considering it impossible; no one, they believe, ought to aspire to the palm of Christian piety while surrounded by the affairs of the world.
I will show them that a strong and resolute person may live in the world without being tainted by it, find spiritual springs amid its salt waters and fly through the flames of temptation without burning the wings on which they soar to God. True, it is no easy task and must be undertaken with much more zeal than many have so far shown, and I hope that this work will help those who undertake it with a generous heart.
-- Introduction to the Devout Life
by St. Francis de Sales