Take great care to preserve your health for love of Our Lord and of his poor members, and beware of doing too much. It is one of the devil's tricks to deceive good souls into doing more than they are able to, until they are capable of nothing at all. [p. 23]

(St Vincent de Paul. From Jacques Delarue, The Holiness of Vincent de Paul, Geoffrey Chapman Ltd, London 1960, 132 pp)