In a nutshell, the Christian doctrine is pretty clear to me: believe in Christ or else you're going to a bad place.
There are certainly many Christians and traditions which either say this explicitly, or at least implicitly; but this isn't the
de facto Christian position. Even among some of the most hardline Fundamentalists you'll see the idea that infants and small children will not be held culpable, or that the un-evangelized will not be necessarily held culpable.
In the language of Lutheranism we speak of "ordinary means" and "extraordinary means"; Martin Luther in his writings gives an example that is helpful to understand this: fire. Fire burns, touch it and you'll get burnt. This is the ordinary, natural action of fire, and yet we read in the book of Daniel that Daniel's three companions were put into the fiery furnace and remained completely unharmed. Fire, indeed, burns--and yet here is an extraordinary case where fire did not burn. God, as the Creator and Author of the universe indeed has established that fire burns, but remains completely free to act outside and above the ordinary to accomplish His purpose (in the case of Daniel's three companions, the fire did not burn them). Likewise, the ordinary means by which we as individuals are brought into Christ and His salvation are the established Means of Word and Sacrament (namely Baptism), this does not render God helpless or bound to the established and ordinary Means. We have, for example, the extraordinary case of the thief on the cross to whom Christ says, "You will be with me in Paradise", and we have in the ancient history of the Church those who were martyred as catechumens, from which the ancient Church spoke of the "baptism of blood".
The Church is bound to the preaching and teaching of the ordinary Means of Grace: we preach the Gospel, we administer the Sacraments, in accordance with Christ's command and the promises attached to these, "That faith comes by hearing and hearing by the word of God" and "All of you who were baptized into Christ have put on Christ", etc.
God is
not so bound. If God so wills that someone from a distant tribe who under no circumstances could ever hear of Christ or His Gospel be saved, there remains nothing that would stop God from accomplishing His purposes.
We know, from Scripture, that God is unwilling that any should perish but that all believe and come to repentance; that it is the will of God that all be saved, that God takes no joy in the destruction of the wicked, that God is good and kind to the thankless and the wicked, that He sends His rain upon the just and the unjust alike (and so on and so forth). So we know that God is the God who saves. We know this because He is the God who condescends to meet us in Jesus Christ, and for the sake of His love for all creatures suffered and offered Himself even in death for the sake of the world, and rising from the dead has overcome and defeated every power that stands in opposition to God--sin, death, hell, the world, and the devil.
God's default disposition toward the world is not damnation, but love, grace, and salvation.
This is why Christians, from across theological traditions, frequently insist that God isn't the one who damns us, we are the ones who damn ourselves. C.S. Lewis speaks of the doors of hell being locked
from the inside. St. Isaac the Syrian says that the only difference between heaven and hell is how we respond to God's universal, impartial, and all-encompassing love, "Love works in two ways" says St. Isaac, "
It torments sinners, as happens here on earth when we are tormented by the presence of a friend to whom we have been unfaithful. And it gives joy to those who have been faithful."
Therefore, I believe the most true Christian response toward the unbelieving, especially the un-evangelized, is what we might call Christian agnosticism: We simply do not know. I also believe that tempered with this there remains also the ancient and historic pious hope of the Church: The hope and the prayer that, indeed,
all will be saved. Therefore the true and faithful Christian response is to understand that we do not know, and in light of our ignorance on this to be a people of prayerful hope. And in this prayerful hope we engage our world with the hopeful promises of God in Christ which are through the Gospel to every last one of us, because the Gospel is for sinners and we are, each and every last one of us, all sinners. The preaching of the Gospel isn't first and foremost about "proselytizing", but announcing the good news of God in Christ Jesus, which is why pastors are supposed to be preachers of the Gospel--preaching the Gospel to their flock, because Christians need to hear the Gospel no less so than those who have never heard it, it is for this reason that St. Paul instructs St. Timothy to "preach the Gospel in and out of season", Timothy was a bishop--a pastor--and thus consecrated to the preaching of the Gospel to his congregation. I, a believing and practicing Christian, need to hear the Gospel preached, because the preaching of the Gospel is efficacious in delivering and nourishing faith.
Now, from what you're revealing to me, at least Catholics and Orthodox do not believe in it strictly. They allow salvation of Muslims, Buddhist, pagans etc who haven't heard the sufficient gospel or anything about Christ at all - on the basis of their conscience or little knowledge they had.
Correct. That the Christian response should be that we believe in the God who gives Himself for the world in Jesus, and thus He is the God who loves the world and saves the world, and we can therefore trust Him to be who He says He is and do what He says He will do; our job as the Church isn't to say who is or isn't saved, but to preach the Gospel, to administer the Sacraments, to be the Christ-bearing people of God out in the world loving the world even as God loves us. For this reason we preach the Gospel, we are called to feed the hungry, serve the needy, forgive our neighbor's trespasses, and be a people bearing and imitating Jesus to the nations. Those who never hear the Gospel, who hear it wrongly, or otherwise don't believe for whatever reason we simply entrust to God. And many of us would say, quite emphatically, that when all is said and done, not one person will be in Hell that doesn't actively and consciously want to be there, as Lewis said, the doors of hell are locked from the inside.
-CryptoLutheran