Catechism of the Catholic Church

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. (863)