The source of the call addressed to all members of the Mystical Body to participate actively in the mission and edification of the People of God, is to be found in the mystery of the Church. The People of God participate in this call through the dynamic of an organic communion in accord with their diverse ministries and charisms. The call has been forcefully repeated in the documents of the Magisterium, particularly since the Second Vatican Ecumenical Council  and thereafter. This is especially true of the last three General Ordinary Assemblies of the Synod of Bishops which reaffirmed the particular identities of the lay faithful and of sacred ministers and religious, in their proper dignity and diversity of functions. These Assemblies encouraged all the faithful to build up the Church by collaborating, in communion, for the salvation of the world.
The necessity and importance of apostolic action on the part of the lay faithful in present and future evangelization must be borne in mind. The Church cannot put aside this task because it is part of her very nature, as the 'People of God', and also because she has need of it in order to realize her own mission of evangelization.
This call for the active participation of all the faithful in the mission of the Church has not been unheard. The 1987 Synod of Bishops observed "The Holy Spirit continues to renew the youthfulness of the Church and has inspired new aspirations towards holiness and the participation of so many lay faithful. This is witnessed, among other ways, in the new manner of active collaboration among priests, religious and the lay faithful; by active participation in the Liturgy; in the proclamation of the Word of God and catechesis; in the multiplicity of services and tasks entrusted to the lay faithful and fulfilled by them; by the flourishing of groups, associations and spiritual movements as well as by lay commitment to the life of the Church and in the fuller and meaningful participation of women in the development of society". This was likewise verified in the preparation for the 1994 Synod of Bishops on Religious Life where it is stated: "Through all, there should be a sincere desire to instill an authentic rapport of communion and of collaboration between the Bishops, institutes of consecrated life, the secular clergy and the laity". In the subsequent Post-Synodal Exhortation the Supreme Pontiff confirmed the specific contribution of religious life in the mission and the building up of the Church.
In effect, a collaboration of all the faithful exists in both orders of the Church's mission; whether it is in the spiritual order, bringing the message of Christ and his grace to men, or, in the temporal one, permeating and perfecting secular reality with the evangelical spirit. This is especially true in the primary areas of evangelization and sanctification - "It is in this sphere most of all that the lay apostolate and the pastoral ministry complete each other". In these areas, the lay faithful of both sexes, have innumerable opportunities to be actively involved. This is possible through bearing consistent witness in their personal, family and social lives by proclaiming and sharing the gospel of Christ in every situation in which they find themselves, and by their involvement with the task of explaining, defending, and correctly applying Christian principals to the problems of today's world. In particular, Pastors are exhorted to "...acknowledge and foster the ministries, the offices and roles of the lay faithful that find their foundation in the Sacraments of Baptism and Confirmation, indeed for a good many of them, in the Sacrament of Matrimony".