From Pope St. John Paul II’s Apostolic Exhortation Familiaris Consortio (1981):
Evangelization, urged on within by irrepressible missionary zeal, is characterized by a universality without boundaries. It is the response to Christ’s explicit and unequivocal command: “Go into all the world and preach the Gospel to the whole creation.”129
The Christian family’s faith and evangelizing mission also possesses this catholic missionary inspiration. The sacrament of marriage takes up and reproposes the task of defending and spreading the faith, a task that has its roots in Baptism and Confirmation,130 and makes Christian married couples and parents witnesses of Christ “to the end of the earth,”131 missionaries, in the true and proper sense, of love and life.
A form of missionary activity can be exercised even within the family. This happens when some member of the family does not have the faith or does not practice it with consistency. In such a case the other members must give him or her a living witness of their own faith in order to encourage and support him or her along the path towards full acceptance of Christ the Savior.132
Animated in its own inner life by missionary zeal, the Church of the home is also called to be a luminous sign of the presence of Christ and of His love for those who are “far away,” for families who do not yet believe, and for those Christian families who no longer live in accordance with the faith that they once received. The Christian family is called to enlighten “by its example and its witness . . . those who seek the truth.”133
Just as at the dawn of Christianity Aquila and Priscilla were presented as a missionary couple,134 so today the Church shows forth her perennial newness and fruitfulness by the presence of Christian couples and families who dedicate at least a part of their lives to working in missionary territories, proclaiming the Gospel and doing service to their fellowman in the love of Jesus Christ.
Christian families offer a special contribution to the missionary cause of the Church by fostering missionary vocations among their sons and daughters135 and, more generally, “by training their children from childhood to recognize God’s love for all people.”136
129 Mc 16:15.
130 Lumen gentium, 11.
131 Acts 1:8.
132 Cf. 1 Pt 3:1 s.
133 Second Vatican Council Lumen gentium, 35; Apostolicam actuositatem, 11.
134 Cf. Acts 18; Rom 16:3-4.
135 Second Vatican Council Ad gentes, 39.
136 Apostolicam actuositatem, 30.
— Familiaris Consortio 54