A lot could be said, but it is late here..
In his oration at the funeral of his father, a convert who became a bishop, St. Gregory of Nazianzus, said:
He was ours even before he was of our fold. His way of living made him such. For just as many of ours are not with us, whose life makes them
other from our body (the Church), so many of those outside belong to us, who by their way of life anticipate the faith, and need (only) the name, having the reality.
Nor do I think the Jews would dare to argue that no one pertained to God except the Israelites, from the time that Israel came to be. . . . they
cannot deny that there were certain men even in other nations who pertained to the true Israelites, the citizens of the fatherland above,
not by earthly but by heavenly association.
St Nilus says..
In every nation, the one who fears God and does justice is acceptable to Him. For it is clear that such a one is acceptable to God and is not to be cast aside, who at his own right time flees to the worship of the blessed knowledge of God. God will not allow him to die in ignorance, but will
lead him to the truth, and will enlighten him with the light of knowledge, like Cornelius.
St Cyril says..
For He is also the God of the gentiles, and has fully satisfied by laws implanted in their hearts, which the Maker has engraved in the hearts of all. For when the gentiles, (Paul) says, not having the law, do by nature the things of the law, they show the work of the law written on their hearts. But since He is not only the Maker and God of the Jews, but also of the gentiles . . . He sees fit by His providence to care not only for those who are of the blood of Israel, but also for all those upon the earth.
"By nature they do the things of the law. . . ." He (Paul) speaks either of those who keep the law of nature, who do not do to others what they do not want to be done to themselves; or, that even the gentiles naturally praise the good and condemn the wicked, which is the work of the law; or, of those who even now, when they do anything good, profess that they have received from God the means of pleasing God. . . . "And their thoughts in turn accusing or even defending, on the day when God will judge the hidden things of men." He speaks of altercations of thought . . . and according to this we are to be judged on the day of the Lord.
Haymo (EO bishop 9th cent.) says..
They show surely that they have the natural law written on their hearts, and they are the law for themselves: because they do the things that the law teaches, even though it was not given to them. For example, the Saracens who have neither the law of Moses nor of the Gospel, while by nature they keep the law, do not commit murder, or commit adultery, or other things, which the law written within them contains; they are a law to themselves. . . . In the second way: When the gentiles . . . naturally do the things . . . because they have the same law of Moses written on their hearts by the inspiration of Almighty God . . . "their conscience bearing witness to them, and their thoughts in turn accusing or even defending." And when will this be? "On the day when the Lord will judge the hidden things of men" according to my Gospel.
Oecumenius (10th cent. EO) says..
"They do the things of the law" using the reasonings of nature for just actions. These are wonderful, not needing a teacher, being their own
lawgivers and fulfillers of the legislation. . . . "Their conscience bearing witness to them," for it is enough in place of the law to have their own conscience testifying for them. . . . At that judgment we do not need external accusers or witnesses . . . but each one's own reasonings
and conscience either accuses or defends.
These are not offered dogmatically, but just as material from my own reflections on this question. They show me that there is at least a significant tradition that those outside the Church can be saved as God wills and as they respond to God. Even in the case of a Saracen, who is not saved by Islam, but despite Islam, and because such a one has turned to God honestly as far as he has been revealed to him.