Catechism of the Catholic Church
898 "By reason of their special vocation it belongs to the laity to seek the kingdom of God by engaging in temporal affairs and directing them according to God's will.... It pertains to them in a special way so to illuminate and order all temporal things with which they are closely associated that these may always be effected and grow according to Christ and maybe to the glory of the Creator and Redeemer." 431
899 The initiative of lay Christians is necessary especially when the matter involves discovering or inventing the means for permeating social, political, and economic realities with the demands of Christian doctrine and life. This initiative is a normal element of the life of the Church:
Lay believers are in the front line of Church life; for them the Church is the animating principle of human society. Therefore, they in particular ought to have an ever-clearer consciousness not only of belonging to the Church, but of being the Church, that is to say, the community of the faithful on earth under the leadership of the Pope, the common Head, and of the bishops in communion with him. They are the Church. 432
900 Since, like all the faithful, lay Christians are entrusted by God with the apostolate by virtue of their Baptism and Confirmation, they have the right and duty, individually or grouped in associations, to work so that the divine message of salvation may be known and accepted by all men throughout the earth. This duty is the more pressing when it is only through them that men can hear the Gospel and know Christ. Their activity in ecclesial communities is so necessary that, for the most part, the apostolate of the pastors cannot be fully effective without it. 433
English Translation of the Cathechism of the Catholic Church for the United States of America © 1997, United States Catholic Conference, Inc.