Apostolicam Actuositatem 29
However, the lay person should learn especially how to perform the mission of Christ and the Church by basing his life on belief in the divine mystery of creation and redemption and by being sensitive to the movement of the Holy Spirit who gives life to the people of God and who urges all to love God the Father as well as the world and men in Him. This formation should be deemed the basis and condition for every successful apostolate.
Since formation for the apostolate cannot consist in merely theoretical instruction, from the beginning of their formation the laity should gradually and prudently learn how to view, judge and do all things in the light of faith as well as to develop and improve themselves along with others through doing, thereby entering into active service to the Church.
These words sum up the modern idea of the lay apostolate (voir, juger, agir) associated first and foremost with the Jeunesse Ouvrière Chrétienne (JOC) under the guidance of the famous Fr J. Cardijn, who was raised to the Cardinalate during the period of the Council. Training for the apostolate must form the whole Christian personality. ‘Inasmuch as the human person is continuously developing and new problems are forever arising, training for the apostolate should be steadily perfected; it requires an ever more thorough knowledge and a continual adaptation of action. While meeting all its demands, a concern for the unity and integrity of the human person must be kept always in the foreground, in order to preserve and intensify its harmony and equilibrium.’ (AA 29)
Karol Wojtyla (P.S. Falla, translator), Source of Renewal, The implementation of the Second Vatican Council, Harper and Row, San Francisco, 1980, 437p. at p. 462.
Karol Wojtyla, Cardijn’s See Judge Act (Joseph Cardijn Digital Library)