lest they, like their forefathers, should be condemned to everlasting punishment

Coleridge, Henry. The Life and Letters of St. Francis Xavier. (1872) pp. 338-9, 347

Letter of St. Francis Xavier written in 29th of January, 1552 (table of contents p. xv )
...
Before their baptism the converts of Amanguchi were greatly troubled and pained by a hateful and annoying scruple—that God did not appear to them merciful and good, because He had never made Himself known to the Japanese before our arrival, especially if it were true that those who had not worshipped God as we preached were doomed to suffer everlasting punishment in hell. It seemed to them that He had forgotten and as it were neglected the salvation of all their ancestors, in permitting them to be deprived of the knowledge of saving truths, and thus to rush headlong on eternal death. It was this painful thought which, more than anything else, kept them back from the religion of the true God.

But by the divine mercy all their error and scruple was taken away. We began by proving to them that the divine law is the most ancient of all. Before receiving their institutions from the Chinese, the Japanese knew by the teaching of nature that it was wicked to kill, to steal, to swear falsely, and to commit the other sins enumerated in the ten commandments, a proof of this being the remorse of conscience to which any one guilty of one of these crimes was certain to be a prey. We showed them that reason itself teaches us to avoid evil and to do good, and that this is so deeply implanted in the hearts of men, that all have the knowledge of the divine law from nature, and from God the Author of nature, before they receive any external instruction on the subject .

If any doubts were entertained on the matter, an experiment might be made in the person of a man without any instruction, living in absolute solitude, and in entire ignorance of the laws of his country. Such a man, ignorant of and a stranger to all human teaching, if he were asked whether it were or were not criminal to kill, to steal, or to commit the other actions forbidden by the law of God, and whether it were right to abstain from such actions, then, I say, this man, so fundamentally without all human education, would most certainly reply in such a manner as to show that he was by no means without knowledge of the divine law. Whence then must he be supposed to have received this knowledge, but from God Himself, the Author of nature ? And if this knowledge is seen among barbarians, what must be the case with civilized and polished nations? This being so, it necessarily follow that before any laws were made by men the divine law existed innate in the hearts of all men. The converts were so satisfied with this reasoning, as to see no further difficulty; so that this net having been broken, they received from us with a glad heart the sweet yoke of our Lord.
...
One of the things that most of all pains and torments these Japanese is, that we teach them that the prison of hell is irrevocably shut, so that there is no egress therefrom. For they grieve over the fate of their departed children, of their parents and relatives, and they often show their grief by their tears. So they ask us if there is any hope, any way to free them by prayer from that eternal misery, and I am obliged to answer that there is absolutely none. Their grief at this affects and torments them wonderfully ; they almost pine away with sorrow. But there is this good thing about their trouble—it makes one hope that they will all be the more laborious for their own salvation, lest they, like their forefathers, should be condemned to everlasting punishment. They often ask if God cannot take their fathers out of hell, and why their punishment must never have an end. We gave them a satisfactory answer, but they did not cease to grieve over the misfortune of their relatives; and I can hardly restrain my tears sometimes at seeing men so dear to my heart suffer such intense pain about a thing which is already done with and can never be undone.

all these [infidels and heretics] are certainly in the way to be lost

Oh, what a miserable state were all men in before the  coming of the Messias; the true God was hardly known  even in Judea, and in every other part of the world  idolatry reigned, so that our forefathers worshipped  stones, and wood, and devils; they worshipped innumerable false gods, but the true God was neither loved nor  known by them. Even now, how many countries are there  in which there are scarcely any Catholics, and all the  rest of the inhabitants are either infidels or heretics ! and  all these are certainly in the way to be lost. What obligation do we not owe to God for causing us to be born,  not only after the coming of Jesus Christ, but also in  countries where the true faith reigns !  

 - St. Alphonsus The Incarnation, Birth, and Infancy of Jesus Christ pp. 291-2