The holy universal Church teaches that it is not possible to worship God truly except in Her and asserts that all who are outside of Her will not be saved.
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 IWhatsoever then you have well in this world, when you recollect to have done any thing good, be very fearful about it, lest the prosperity granted you be your recompense for the same good. And when you behold poor men doing any thing blameably, fear not, seeing that perhaps those whom the remains of the slightest iniquity defiles, the fire of honesty cleanses.
Pope Gregory IThe 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 I