1. The difficulties that sometimes accompany the development of evangelisation highlight a delicate problem whose solution cannot be sought in purely historical or sociological terms: the problem of the salvation of those who do not visibly belong to the Church. We are not given the opportunity to scrutinise the mystery of divine action in minds and hearts, to assess the power of Christ's grace in taking possession, in life and in death, of those whom 'the Father has given him', and whom he himself has proclaimed he does not want to 'lose'. We hear this repeated in one of the Gospel readings proposed for the Mass for the dead (cf. Jn 6:39-40).
But, as I wrote in the Encyclical Redemptoris Missio, the gift of salvation cannot be limited "to those who explicitly believe in God and have entered the Church. If salvation is destined for all, it must be made available to all in concrete terms". And, admitting that it is practically impossible for many people to access the Christian message, I added: "Many people do not have the opportunity to know or accept the revelation of the Gospel or to enter the Church. They live in socio-cultural conditions that do not allow it, and they have often been educated in other religious traditions" (Redemptoris Missio, 10).
We must recognise that, as far as human foresight and knowledge are concerned, this practical impossibility seems destined to continue for a long time, perhaps even until the final completion of the work of evangelisation. Jesus himself warned that only the Father knows "the times and moments" he has set for the establishment of his Kingdom in the world (cf. Acts 1:7).
2. However, what I have said above does not justify the relativistic position of those who believe that a way of salvation can be found in any religion, even independently of faith in Christ the Redeemer, and that interreligious dialogue should be based on this ambiguous conception. This is not the Gospel-compliant solution to the problem of the salvation of those who do not profess the Christian Creed. Instead, we must maintain that the path to salvation always passes through Christ, and that it is therefore the task of the Church and her missionaries to make him known and loved at all times, in every place and in every culture. Outside of Christ, "there is no salvation." As Peter proclaimed before the Sanhedrin, from the beginning of the apostolic preaching: "There is no other name given to men under heaven by which we must be saved" (Acts 4:12).
Even for those who, through no fault of their own, do not know Christ and do not recognise themselves as Christians, the divine plan has provided a way of salvation. As we read in the conciliar decree on missionary activity Ad Gentes, we believe that "God, through ways known only to himself, can lead men who through no fault of their own are ignorant of the Gospel" to the faith necessary for salvation (Ad Gentes, 7). Of course, the condition "through no fault of their own" cannot be verified or assessed by human evaluation, but must be left solely to divine judgement. For this reason, in the Constitution Gaudium et Spes, the Council declares that in the heart of every person of good will "grace works invisibly" and that "the Holy Spirit gives everyone the possibility of coming into contact, in the way known to God, with the Paschal Mystery" (Gaudium et Spes, 22).
3. It is important to emphasise that the path to salvation taken by those who ignore the Gospel is not a path outside Christ and the Church. The universal will to save is linked to the unique mediation of Christ. The First Letter to Timothy affirms this: "God our Saviour, who wants all men to be saved and come to the knowledge of the truth. For there is one God, and there is one mediator between God and humankind, the man Christ Jesus, who gave himself as a ransom for all” (1 Tim 2:3-6). Peter proclaims this when he says that "there is no salvation in anyone else," and calls Jesus the "cornerstone" (Acts 4:11-12), highlighting the necessary role of Christ as the foundation of the Church.
This affirmation of the “uniqueness” of the Saviour originates from the words of the Lord himself, who says that he came “to give his life as a ransom for many” (Mark 10:45), that is, for humanity, as St Paul explains when he writes: “One died for all” (2 Cor 5:14 cf. Rom 5:18). Christ obtained universal salvation by the gift of his life: no other mediator has been established by God as Saviour. The unique value of the sacrifice of the Cross must always be recognised in the destiny of every human being.
4. And since Christ works salvation through his mystical Body, which is the Church, the way of salvation is essentially linked to the Church. The axiom extra Ecclesiam nulla salus – "outside the Church there is no salvation" – enunciated by Saint Cyprian (Epist 73,21: PL 1123 AB), belongs to Christian tradition and was included in the Fourth Lateran Council (Denz.-S. 802), in the bull Unam Sanctam of Boniface VIII (Denz.-S. 870) and in the Council of Florence (Decretum pro Jacobitis, Denz.-S. 1351).
The axiom means that for those who are not ignorant that the Church was founded by God through Jesus Christ, it is necessary to enter and persevere in it in order to obtain salvation (cf. Lumen Gentium, 14). For those who have not received the proclamation of the Gospel, as I wrote in the Encyclical Redemptoris Missio, salvation is accessible through mysterious ways, inasmuch as divine grace is conferred on them by virtue of Christ's redemptive sacrifice, without external adherence to the Church but always in relation to it (cf. Redemptoris Missio, 10). This is a "mysterious relationship": mysterious for those who receive it, because they do not know the Church and indeed sometimes reject it externally; mysterious also in itself because it is linked to the saving mystery of grace, which involves an essential reference to the Church founded by the Saviour.
In order to be effective, saving grace requires adherence, cooperation, and a yes to divine self-giving: and such adherence is, at least implicitly, oriented towards Christ and the Church. Therefore, we can also say sine Ecclesia nulla salus – 'without the Church there is no salvation': adherence to the Church, the mystical Body of Christ, however implicit and mysterious, is an essential condition for salvation.
5. Religions can have a positive influence on the destiny of those who belong to them and follow their teachings with sincerity of spirit. But if the decisive action for salvation is the work of the Holy Spirit, we must bear in mind that man receives his salvation only from Christ, through the Holy Spirit. It begins already in earthly life, which grace, accepted and reciprocated, makes fruitful, in the evangelical sense, for earth and heaven.
Hence the importance of the indispensable role of the Church, which "is not an end in itself but fervently seeks to be wholly of Christ, in Christ and for Christ, and wholly of men, among men and for men". This role is therefore not 'ecclesiocentric', as has sometimes been said: the Church does not exist or work for itself, but is at the service of humanity called to divine filiation in Christ (cf. Redemptoris Missio, 19). It therefore exercises an implicit mediation even towards those who are ignorant of the Gospel.
However, this should not lead to the conclusion that its missionary activity is less necessary in such circumstances. Quite the contrary. In fact, those who are ignorant of Christ, through no fault of their own, find themselves in a condition of darkness and spiritual famine, which often has negative repercussions on a cultural and moral level. The missionary activity of the Church can provide them with the conditions for the full development of Christ's saving grace, proposing full and conscious adherence to the message of faith and active participation in the life of the Church in the sacraments.
This is the theological line drawn from Christian tradition. The Magisterium of the Church has followed it in doctrine and practice as the way marked out by Christ himself for the Apostles and for missionaries of all times.
[Pope John Paul II, General Audience, 31 May 1995]