30 The training for the apostolate should start with the children's earliest education. In a special way, however, adolescents and young persons should be initiated into the apostolate and imbued with its spirit. This formation must be perfected throughout their whole life in keeping with the demands of new responsibilities. It is evident, therefore, that those who have the obligation to provide a Christian education also have the duty of providing formation for the apostolate. In the family parents have the task of training their children from childhood on to recognize God's love for all men. By example especially they should teach them little by little to be solicitous for the material and spiritual needs of their neighbor. The whole family in its common life, then, should be a sort of apprenticeship for the apostolate. Children must be educated, too, in such fashion that transcending the family circle, they may open their minds to both ecclesiastical and temporal communities. They should be so involved in the local community of the parish that they will acquire a consciousness of being living and active members of the people of God. Priests should focus their attention on the formation of the laity for the apostolate in their catechetics, their ministry of the word, their direction of souls, and in their other pastoral services. Schools, colleges, and other Catholic educational institutions also have the duty to develop a Catholic sense and apostolic activity in young persons. If young people lack this formation either because they do not attend these schools or because of any other reason, all the more should parents, pastors of souls, and apostolic organizations attend to it. Teachers and educators on the other hand, who carry on a distinguished form of the apostolate of the laity by their vocation and office, should be equipped with that learning and pedagogical skill that are needed for imparting such education effectively. Likewise, lay groups and associations dedicated to the apostolate or other supernatural goals, should carefully and assiduously promote formation for the apostolate in keeping with their purpose and condition. Frequently these groups are the ordinary vehicle for harmonious formation for the apostolate inasmuch as they provide doctrinal, spiritual, and practical formation. Their members meet in small groups with their associates or friends, examine the methods and results of their apostolic activity, and compare their daily way of life with the Gospel. Formation of this type must be so organized that it takes into account the whole lay apostolate, which must be carried on not only among the organized groups themselves but also in all circumstances throughout one's whole life, especially one's professional and social life. Indeed, everyone should diligently prepare himself for the apostolate, this preparation being the more urgent in adulthood. For the advance of age brings with it a more open mind, enabling each person to detect more readily the talents with which God has enriched his soul and to exercise more effectively those charisms which the Holy Spirit has bestowed on him for the good of his brethren.
Source: Apostolicam Actuositatem (Vatican.va)