Letter 804: The priesthood is a sacred trust, not a career.

To Isidore. Just as Jerusalem—to make use of a vivid example—when it was armed with the divine alliance, stood upright in resistance and set up its trophies without bloodshed; but when it was abandoned by that alliance, because of its trespass against it, hostile fire easily brought it down: so too the soul, when it acts hedged about by the inclination from above through its steadfastness, easily overcomes its enemies; but when it sins, it will here be captured by the fire of the passions, and there be punished by the fire of judgment.

Ὥσπερ, ἵνα καὶ ἐναργεῖ παραδείγματι χρήσωμαι, Ἱερουσαλὴμ, ὅτε μὲν τῇ θείᾳ συμμαχίᾳ ὥπλιστο, ὀρθή ἐστῶσα ἀπηντῆ καὶ ἀναιμακτὶ τὰ τρόπαια ἵστη· ὅτε δὲ ταύτης διὰ τὸ ἐπιλυτῆσαι κατ’ αὐτῆς, ἐράτητο, πῦρ πολέμιον αὐτὴν ῥᾳδίως ἔκλινεν· οὕτω καὶ ψυχή, ὅταν μὲν τῇ ἄνωθεν ῥοπῇ δι’ εὐστάθειαν πράττῃ περιφράττηται, ῥᾳδίως τοὺς πολεμίους καταγωνίζεται· ὅταν δ’ ἁμάρτῃ, ἐνταῦθα μὲν τῷ πυρὶ τῶν παθῶν ἁλώσεται, ἐκεῖσε δὲ τῷ τῆς κρίσεως τιμωρηθήσεται.