VOI FORSE SAPETE
Address of our holy father of blessed memory, Paul VI, to a general audience, 1 June, 1966.
You may already know that We want very much to take the Church, again the Church, as the subject for this little General Audience talk. The strong but gentle voice of the Council on this theme still resounds in Our mind. We feel that we honor you, Our dear visitors, by echoing some syllables of that voice which speaks precisely of the Church, which speaks of you, for you are the Church.
Think it over carefully. You are the Church, which means that you belong to the Church, to the holy Church of God, to the great assembly called together by Christ, to the living community of His word and His grace, to His Mystical Body. This consciousness of belonging to the Church must grow ever clearer in us. It is a consciousness of our dignity, for in the Church we are truly adopted sons of God and brothers of Christ, living through Him in the Holy Spirit. It is a consciousness of our good fortune. What greater fortune could we have than that of being admitted to this society of salvation? It is a consciousness of duty, of commitment (as people call it nowadays). This is obvious from the fact that someone who belongs to the Church is called one of the faithful -- that is, one who adheres, who is steadfast and permanent.
And so, if it is something very wonderful and very important to belong to the Church, an urgent question comes automatically to mind. Do I really belong to the Church? Who belongs to it? How is this belonging conferred?
At first glance, the reply is an easy one. Everyone knows it. It is through Baptism that a person enters the Church. The Council,  and before that the whole of Christian tradition, says that the faithful are incorporated into the Church through Baptism.
At this point We ought, by rights, to offer a full explanation of this Sacrament. But We will limit Ourself to expressing the hope that Christian people may welcome, favor, and come to understand and appreciate the work which the liturgical reform is doing to place the Sacrament of Baptism in proper perspective in the minds and customs of the faithful. This is something of the greatest importance for a true concept of Christian life.
For the present, let Us rather ask another question. Are all those who have been baptized, even those who are separated from Catholic unity, in the Church? In the true Church? In the one Church? Yes. This is one of the great truths of Catholic tradition, and the Council has repeatedly confirmed it.  It is connected with the article of the Creed which we sing at Mass: _Confiteor unum baptisma in remissionem peccatorum._  It is connected with the great theological polemics of the early centuries, concluded in particular with the authority of St. Augustine. In the disputes with the Donatists, he affirmed that "the Church has had the very happy custom of correcting whatever is false in schismatics and heretics, but not of repeating what has been give (by them, that is, Baptism); of healing what is wounded, but not of healing what is healthy." 
To cite a recent document of the Church's magisterium, this is what the encyclical _Mystici Corporis_ teaches: "With the washing of the purifying water, those who are born to this mortal life, are reborn from the death of (original) sin and are made members of the Church. "  This doctrine is the basis of our ecumenism, which makes us regard as brothers the Christians who are separated from us, and all the more so if, with Baptism and faith in Christ and in the mystery of the Blessed Trinity, they preserve many other treasures of our common Christian heritage. 
But is Baptism and a certain amount of faith enough to belong fully to the Church? We have to recall that this fullness, this perfect communion is a profound and inextinguishable requirement of the religious order founded by Christ. If belonging to the Church in at least an initial or partial way is highly valuable, then it is just as desirable for this belonging to reach its full measure. The Church is one and unique. There are not several Churches, standing unto themselves and sufficient unto themselves.  The sovereign law of unity intimately governs the religious society established by the Lord. Let us never forget the powerful words of St. Paul: "Be careful to preserve the unity of the Spirit in the bond of peace: one single body, one single Spirit, as you have been called in one single hope; there is one Lord, one faith, one Baptism, one God and Father of all."  It is to this perfect organic unity and "to overcome the obstacles which stand in the way of full ecclesiastical communion that our ecumenical movement tends." 
Now, two other big questions arise. How will the catechumens, or better still, all those who do not know the Gospel and the Church, be saved? This is the first question, and an enormous one. The other is this: Do sinners, who are not in God's grace, belong to the Church? We will not answer these questions here, for that would involve distinctions and details requiring long and careful consideration. We will simply say, with regard to the first, that a person can belong to the Church in reality, or _in voto_ virtually, by desire (as the catechumens) or even 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. That mercy can link to mankind saved by Christ, and therefore to the Church, all the immense multitudes of human beings "who sit in the shadow of death,"  but who are themselves created and loved by the divine goodness. 
With regard to the second question We will simply offer this both strange and wonderful truth: even sinners can belong to the Church. This is a doctrine opposed by those who claim that the Church on earth is composed only of saints.  Sin interrupts union with God, but if it doesn't interrupt adherence to the communion of salvation which is the Church (as does a sin that is expressly directed against belonging to the Church -- heresy, schism, apostasy -- or that implies separation from the community, which means excommunication), then it can find its redemption in this institution which was established specifically in order to save men. Recall the parable of the net: "The kingdom of heaven is like a net cast into the sea that caught every kind of fish." 
But if you wish to sum up and remember all of this very important doctrine on belonging to the Church, think rather of another twofold image with which Jesus pictures the Church -- that of the sheepfold and of the flock.  Take the greatest care to be inside the sheepfold of Christ and to be among the fortunate number of His flock. This is the wish that We desire to strengthen and reinforce with Our apostolic blessing.