The pastor should always be pure in thought ... no impurity ought to pollute him who has undertaken the office of wiping away the stains in the hearts of others ... for the hand that would cleanse from dirt must be clean, lest, being itself sordid with clinging mire, it soil whatever it touches all the more.
Pope Gregory IIf the work of God could be comprehended by reason, it would no longer be wonderful, and faith would have no merit if reason provided proof.
Pope Gregory I