11 Secular Institutes, although not Religious institutes involve a true and full profession of the evangelical counsels in the world. This profession is recognized by the Church and consecrates to God men and women, lay and clerical, who live in the world. Hence they should make a total dedication of themselves to God in perfect charity their chief aim, and the institutes themselves should preserve their own proper, i.e., secular character, so that they may be able to carry out effectively everywhere in and, as it were, from the world the apostolate for which they were founded. It may be taken for granted, however, that so great a task cannot be discharged unless the members be thoroughly trained in matters divine and human so that they are truly a leaven in the world for the strengthening and growth of the body of Christ. Superiors, therefore, should give serious attention especially to the spiritual training to be given members as well as encourage their further formation.
Source: Perfectae Caritatis (Vatican.va)