… it needs also to be recalled that if a non-Catholic Christian, for reasons of conscience and having been convinced of Catholic truth, asks to enter into the full communion of the Catholic Church, this is to be respected as the work of the Holy Spirit and as an expression of freedom of conscience and of religion. In such a case, it would not be a question of proselytism in the negative sense that has been attributed to this term.[49] As explicitly recognized in the Decree on Ecumenism of the Second Vatican Council, “it is evident that the work of preparing and reconciling those individuals who desire full Catholic communion is of its nature distinct from ecumenical action, but there is no opposition between the two, since both proceed from the marvelous ways of God”.[50] Therefore, the work of ecumenism does not remove the right or take away the responsibility of proclaiming in fullness the Catholic faith to other Christians, who freely wish to receive it.
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Although non-Christians can be saved through the grace which God bestows in “ways known to him”,[21] the Church cannot fail to recognize that such persons are lacking a tremendous benefit in this world: to know the true face of God and the friendship of Jesus Christ, God-with-us.
[49] The term proselytism originated in the context of Judaism, in which the term proselyte referred to someone who, coming from the gentiles, had passed into the Chosen People. So too, in the Christian context, the term proselytism was often used as a synonym for missionary activity. More recently, however, the term has taken on a negative connotation, to mean the promotion of a religion by using means, and for motives, contrary to the spirit of the Gospel; that is, which do not safeguard the freedom and dignity of the human person. It is in this sense that the term proselytism is understood in the context of the ecumenical movement: cf. The Joint Working Group between the Catholic Church and the World Council of Churches, “The Challenge of Proselytism and the Calling to Common Witness” (1995).