Apostolicam Actuositatem §16

¹⁶ The individual apostolate, flowing generously from its source in a truly Christian life (cf. John 4:14), is the origin and condition of the whole lay apostolate, even of the organized type, and it admits of no substitute. Regardless of status, all lay persons (including those who have no opportunity or possibility for collaboration in associations) are called to this type of apostolate and obliged to engage in it. This type of apostolate is useful at all times and places, but in certain circumstances it is the only one appropriate and feasible. There are many forms of the apostolate whereby the laity build up the Church, sanctify the world, and give it life in Christ. A particular form of the individual apostolate as well as a sign specially suited to our times is the testimony of the whole lay life arising from faith, hope, and charity. It manifests Christ living in those who believe in Him. Then by the apostolate the spoken and written word, which is utterly necessary under certain circumstances, lay people announce Christ, explain and spread His teaching in accordance with one's status and ability, and faithfully profess it. Furthermore, in collaborating as citizens of this world, in whatever pertains to the upbuilding and conducting of the temporal order, the laity must seek in the light of faith loftier motives of action in their family, professional, cultural, and social life and make them known to others when the occasion arises. Doing this, they should be aware of the fact that they are cooperating with God the creator, redeemer, and sanctifier and are giving praise to Him. Finally, the laity should vivify their life with charity and express it as best they can in their works. They should all remember that they can reach all men and contribute to the salvation of the whole world by public worship and prayer as well as by penance and voluntary acceptance of the labors and hardships of life whereby they become like the suffering Christ (cf. 2 Cor. 4:10; Col. 1:24).