There was one spirit from a non-Christian country who had lived a good and thoughtful life according to his religion in this world. When he heard some Christian spirits discussing their creeds (spirits talking to each other reason much more exhaustively and acutely than people on earth, especially about what is good and true), he was astonished to find that they quarreled. He said he did not want to listen, since they were arguing on the basis of deceptive appearances. His advice to them was, “If I am a good person, I can know what is true simply from its goodness, and I can be open to what I do not know.”
I have been taught by a great many instances that if non-Christians have lived decent lives, intent on obedience and appropriate deference and in mutual thoughtfulness as their religion requires so that they have acquired a measure of conscience, they are accepted in the other life and are taught by angels about matters of goodness and truth with most sensitive care. Once they have been taught, they behave unpretentiously, intelligently, and wisely and readily accept and absorb truths. This is because no false principles have taken form to oppose truths of faith, principles that would need to be ousted, let alone slanders against the Lord, as is the case for many Christians whose treasured concept of the Lord is simply of an ordinary human being. It is different for non-Christians. When they hear that God became a person here and made himself known in the world, they acknowledge it immediately and revere the Lord. They say that of course God made himself known; after all, he is the God of heaven and earth, and the human race belongs to him.
It is a divine truth that there is no salvation apart from the Lord, but this needs to be understood as meaning that there is no salvation that does not come from the Lord. There are many planets in the universe, all full of inhabitants. Hardly any of them know that the Lord took on a human nature on our planet. Still, though, since they do revere the Divine Being in human form, they are accepted and led by the Lord.
from Heaven and Hell, Sections 320, 321