Catechism of the Catholic Church
928 "A secular institute is an institute of consecrated life in which the Christian faithful living in the world strive for the perfection of charity and work for the sanctification of the world especially from within." 472
929 By a "life perfectly and entirely consecrated to [such] sanctification," the members of these institutes share in the Church's task of evangelization, "in the world and from within the world," where their presence acts as "leaven in the world." 473 "Their witness of a Christian life" aims "to order temporal things according to God and inform the world with the power of the gospel." They commit themselves to the evangelical counsels by sacred bonds and observe among themselves the communion and fellowship appropriate to their "particular secular way of life." 474
English Translation of the Cathechism of the Catholic Church for the United States of America © 1997, United States Catholic Conference, Inc.