St Vincent de Paul's talk to Daughters of Charity:

“Sometimes we dislike each other without knowing why. Often it's a touch of jealousy or envy. Our dislike for a Sister can come from hearing her eat or seeing her do some other action. This dislike, if we dwell on it, will inevitably lead to disunity. Oh my Daughters, do everything you can to overcome it.” [p. 90]

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