Your struggles and temptations may differ according to your various situations, but all of you cherish the same basic hope to the faithful to Christ and to put his message into practice. You all cherish the same basic hope for a decent life for yourselves and an even better life for your children. All of you must toil and work and bear the sufferings and disappointments common to humanity, but as believers you are endowed with faith, hope and charity. And often your charity reaches heroic dimensions within your families or among your neighbours and co-workers. To the extent that your resources and duties in life permit, you are called to support and actively to participate in Church activities.
It is within the everyday world that you, the laity, must bear witness to God’s Kingdom; through you the Church’s mission is fullfilled by the power of the Holy Spirit. The Council taught that the specific task of the laity is precisely this: to “seek the Kingdom of God by engaging in temporal affairs and by ordering them according to the plan of God” (Ibid. 31). You are called to live in the world, to engage in secular professions and occupations, to live in those ordinary circumstances of family life and life in society from which is woven the very web of your existence. You are called by God himself to exercise your proper functions according to the spirit of the Gospel and to work for the sanctification of the world from within, in the manner of leaven. In this way you can make Christ known to others, especially by the witness of your lives. It is for you as lay people to direct all temporal affairs to the praise of the Creator and Redeemer (Cfr. Lumen Gentium, 31).
The temporal order of which the Council speaks is vast. It encompasses the social, cultural, intellectual, political and economic life in which all of you rightly participate. As lay men and women actively engaged in this temporal order, you are being called by Christ to sanctify the world and to transform it. This is true of all work, however exalted or humble, but it is especially urgent for those whom circumstances and special talent have placed in positions of leadership or influence: men and women in public service, education, business, science, social communications, and the arts. As Catholic lay people you have an important moral and cultural contribution of service to make to the life of your country. Much will be required of the person entrusted with much” (Luc. 12, 48). These words of Christ apply not only to the sharing of material wealth or personal talents, but also to the sharing of one’s faith. — from the pope’s address to American laypeople on September 18, 1987