The Soul And The Body's Healing

Et revera majus miraculum est de propria carne fomitem luxuriae eradicare, quam expellere immundos spiritus de corporibus alienis; et magnificentius signum est virtute patientiae truculentos motus iracundiae cohibere, quam aeris principatibus imperare; plusque est exclusisse edacissimos de corde proprio tristitiae morbos, quam valetudines alterius febresque corporeas expulisse. Postremo multis modis praeclarior virtus sublimiorque profectus est, animae propriae curare languores, quam corporis alieni. Quanto enim haec sublimior carne est, tanto praestantior ejus est salus; quantoque pretiosioris excellentiorisque est substantiae, et tanto gravioris ac perniciosioris est et ruinae. Sanctus Ioannes Cassianus, Collationes, Collatio XV, Quae est secunda abbatis Nesterotis, De Charismatibus Divinis, Caput VIII, Quod mirabilius sit de semetipso vitia, quam de altero daemones extrusisse Source: Migne PL 49.1007b-1008a

And in truth it is a greater miracle to root out from one's own flesh the inclination to lust than to expel unclean spirits from the bodies of others, and it is a greater sign to restrain the wild motions of anger by the virtue of patience than to command the powers of the air, and it is greater to have shut out from one's heart the devouring pangs of gloominess than to have expelled sickness and fever from the body of another. Finally it is in many ways a greater virtue and a more glorious achievement to cure the infirmities of one's own soul than those of the body of another. For as much as the soul is greater than the flesh, so is its salvation more important, and as much as the soul is more precious and more excellent, so its ruin is more grievous and more perilous. Saint John Cassian, Conferences, Conference 15, The Second of Abbot Nesteros, On Divine Gifts, Chapter 8, That it is more wonderful to have cast out one's faults from one's self than demons from another.