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 IGod is called jealous, angered, repentant, merciful, and foreknowing. These simply mean that, because He guards the chastity of every soul, He can, in human fashion, be called jealous, although He is not subject to any mental torment.
Pope Gregory IThere are in truth three states of the converted: the beginning, the middle, and the perfection. In the beginning they experience the charms of sweetness; in the middle the contests of temptation; and in the end the fullness of perfection.
Pope Gregory IWhoever wishes to hold the fortress of contemplation must first of all train in the camp of action.
Pope Gregory INow if the wearing of fine and precious robes were not a fault, word of God would never have so carefully expressed this. For no one seeks costly garments except for vainglory, that he may seem more honorable than others; for no one wishes to be clothed with such, where he cannot be seen by others.
Pope Gregory I