The following is a summary of the teaching of the Magisterium Church, and of the Church Fathers and Doctors, on the dogma expressed in the words, "Extra Ecclesiam Nulla Salus." Further details, arguments, and explanations can be found at the blog, Extra Ecclesiam Nulla Salus, from which much of this material has been summarized.
In brief, the Church's understanding of this doctrine is that all who are saved receive the grace of salvation in and through Christ; this grace always contains a reference to Christ's mystical body, the Church, and brings the justified person into a mysterious contact with that Church. Hence also, those who know God's plan to save men as members of his mystical body, are obliged to be united to this Church, and commit a grave fault by rejecting it. But those who are, without their fault, unaware of this plan of God, can be saved without belonging visibly to the Church, and only united to it through the mysterious bond of grace and charity working in their soul, which unites them spiritually with all who have grace, unites them with the Church. In this sense they are saved in and through the Church; without belonging to it in this sense (Extra Ecclesiam) they would not be saved.
Principles Regarding Salvation - an overview of principles
regarding the salvation of non-Christians.
Extra Ecclesiam Nulla Salus on the web - relevant articles on the teaching of "Extra Ecclesiam", the role of the Church in justification, etc.
Comment on Extra Ecclesiam Nulla Salus - here you can make comments on this page or on the doctrine.
The Council of Florence taught that "all those who are outside the catholic church... cannot share in eternal life... unless they are joined to the catholic church before the end of their lives" and that "nobody can be saved, no matter how much he has given away in alms and even if he has shed his blood in the name of Christ, unless he has persevered in the bosom and the unity of the catholic church." This is one of the most well-known known expressions of the Church dogma that "there is no salvation outside the Church", Extra Ecclesiam Nulla Salus.
Pius IX clearly says that all those who are invincibly ignorant, and yet live upright lives ready to obey God, will be saved. God does not allow anyone who is not guilty of deliberate sin to suffer eternal punishment.
Q: But if a man through no fault of his own is outside the Church,
can he be saved? (A.9 Q.29)
A: If he is outside the Church through no fault of his, that is, if he is in good faith, and if he has received Baptism, or at least has the implicit desire of Baptism; and if, moreover, he sincerely seeks the truth and does God's will as best he can such a man is indeed separated from the body of the Church, but is united to the soul of the Church and consequently is on the way of salvation.
To be united to the soul of the Church means to share in the gifts of the Holy Spirit, who is the soul of the Church--above all, to share in faith, hope, and charity. Thus according to the teaching of Pope Pius X, a person who is outside of the Church, yet not by his own fault, can posssess the theological virtues, and be on the way to salvation.
Under Pius XII, the Holy Office sent a letter to the Archbishop of Boston, clarifying the Feeney case, and the interpretation of the dogma "Extra Ecclesiam Nulla Salus". The main points of this clarification:
1) The Saviour decreed that the Church be a means of salvation
without which no one can enter the kingdom of eternal glory.
2) At the same time, God has willed that the effects of the helps to salvation, which are necessary to be saved, can be obtained in certain circumstances when those helps are used only in desire or longing.
3) Statement number 2 applies to the Church, inasmuch as she is the general help to salvation.
4) Therefore, that one may obtain eternal salvation, it is not always required that a person be incorporated into the Church actually, but it is necessary to be united at least by desire and longing.
5) This desire need not be explicit; when a person has invincible ignorance, God accepts also an implicit desire, which is included in the disposition of soul by which someone wants his will to be conformed to God's will.
6) This desire must be animated by perfect charity, and the person must have supernatural faith.
The Second Vatican Council teaches in Lumen Gentium that "Those also can attain to salvation who through no fault of their own do not know the Gospel of Christ or His Church, yet sincerely seek God and moved by grace strive by their deeds to do His will as it is known to them through the dictates of conscience." It references the above letter of the Holy Office. The Council thus clearly intends to teach that the implicit desire for Christ, included in these persons' "sincere seeking of God", together with their doing God's will inasmuch as they obey their conscience, is a sufficient disposition for them to receive the free grace of justification.
See also the post: Ad
Gentes on the Salvation of non-Christians, which examines the
textual development of the passage of Ad Gentes that addresses this
Paul VI, in Voi Forse Sapete, teaches very clearly that both catechumens and those "who do not know the Gospel and the Church" can be saved, belonging to the Church either by desire, or by "properly directing a life that may be deprived of any explicit knowledge of Christianity, but that is, because of the person's moral uprightness, open to a mysterious mercy of God."
"Since salvation is offered to all, it must be made concretely available to all. But it is clear that today, as in the past, many people do not have an opportunity to come to know or accept the gospel revelation or to enter the Church. The social and cultural conditions in which they live do not permit this, and frequently they have been brought up in other religious traditions. For such people salvation in Christ is accessible by virtue of a grace which, while having a mysterious relationship to the Church, does not make them formally part of the Church but enlightens them in a way which is accommodated to their spiritual and material situation" (Redemptoris Missio).
This text is quite clear. Those who either do not know about Christ, or have obstacles to accepting Christ that arise from their religious or cultural traditions, and which make them bear no guilt for their non-acceptance of Christ, can be saved by a grace that works in them in the situation in which they are.
St. Paul in Romans 2:2-29 teaches:
1.) God will render to every man according to his works. Good to
those who do good, and evil to those who do evil.
2.) It is possible for men to do by nature those things that are of the law, and to act according to their conscience, and by fulfilling this law on their hearts, they may be justified.
3.) Being a true Jew is a matter of a circumcision “of the heart”, and is something within. In fact, since St. Paul is referring this to those who have not received the external law, but fulfill the law written on their hearts, this is akin to saying that they are “implicitly” Jews, on account of the interior circumcision of the heart and spirit.
By saying that God will judge the secrets of men "by Jesus Christ," he is implying that these Gentiles have implicit faith in Christ.
St. Peter in Acts 10:34-36 teaches that God always (thus before and after the preaching of the Gospel) and everywhere (thus also among those who have not heard of Christ) accepts those who fear him and do what is right.
The Scripture passages that are sometimes used to argue against salvation by implicit faith are inadequate to prove the point.
If men before Christ could be saved by implicit faith in Christ, then we have to say that those who, without any fault on their part, are unable to have explicit faith in Christ, are also able to be saved by implicit faith... otherwise God would be withdrawing his grace on account of Christ's coming, an absurd consequence.
St. Justin Martyr says that all who lived, and all who now live according to reason "are Christians", clearly recognizing the possibility of someone implicitly being a Christian, and consequently, the possibility of being saved through such an implicit acceptance of and obedience to Christ. Origen teaches something similar, that even the pagans can meet god as they sacrifice, though not on account of their sacrifices.
St. Irenaeus, too, says that all who feared and loveed God, practiced justice and piety towards their neighbors, and desired to see Christ, insofar as they were able to do so, will be saved. Since many were not able to have an explicit desire to see Christ, but only implicit, it is clear that for St. Irenaeus this is enough.
St. Gregory Nazianzus says that his Father's character before his conversion "made him one of us" and that the same is true of many who are "without", who need "only the name of that which they indeed possess." In other words, by their charity of their life, they are united to Christians in Christ, even before they explicitly believe in Christ.
St. John Chrysostom indicates his belief that those who seek God genuinely will be brought to an explicit faith in Christ. Nonetheless it is clear that justification and charity can precede explicit faith.
Pope St. Clement teaches that the grace of salvation has been made available to the whole world by Christ's death, and proves this by the examples of those before Christ who were saved through their faith in God. Many after Christ's coming , who have faith in God, but cannot have explicit faith in Christ, fit Clement's description of justified persons, and therefore would seem to be included in those whom he teaches are saved through Christ.
St. Augustine teaches that those who are visibly outside of the Church, and even those in heresies and pagan superstitions can possess charity, and be really within it.
According to the teaching of St. Thomas Aquinas, a person can be justified before receiving baptism, through the desire, implicit or explicit, he has for it.
According to Aquinas a person can be justified, both before and after Christ, while having only implicit faith in Christ. He does hold, however, like Chrysostom and others, that if such a person remains faithful to God, God will bring them to explicit faith in him.