The laity are made to share in the priestly, prophetical, and kingly office of Christ; they have therefore, in the Church and in the world, their own assignment in the mission of the whole People of God."… who are consecrated to God in their own special manner and serve the salvific mission of the Church through the profession of the evangelical counsels" (CCC 873).
Catholics have always been called to lead a Christian State of Life, and the writings that came out of the Second Vatican Council only serve to underline this point. This is seen most famously in Pope
Paul VI’s decree on the apostolate of the laity, Apostolicam Actuositatem , and his dogmatic constitution of the Church, Lumen Gentium. In these papal decrees we are recognized as apostles of Christ, and vested with the same obligations. We are charged with the grave responsibility of ministering to our brothers and sisters in Christ in all that we do and say. Furthermore, as unified members of the Body of Christ we are called to participate in the salvific mission of the Church. All of this is made clear in several ways throughout the aforementioned writings.
In all respects, these two works serve to address the secular nature of the laity. Through the power of Christ, and His saving grace, we are able to minister to our brethren; not despite our secular nature, but rather by virtue of it. To paraphrase a quote attributed to St. Francis of Assisi, each of us must preach the gospel in every aspect of our lives; even when not speaking at all. Our actions must be a demonstration of our faith in Christ, our adoration of Him. The role of Christ in our apostleship is addressed in depth in the Apostolicum Actuositatem: Since Christ, sent by the Father, is the source and origin of the whole apostolate of the Church, the success of the lay apostolate depends upon the laity's living union with Christ, in keeping with the Lord's words, "He who abides in me, and I in him, bears much fruit, for without me you can do nothing" (John 15:5)… Neither family concerns nor other secular affairs should be irrelevant to their spiritual life, in keeping with the words of the Apostle, "What-ever you do in word or work, do all in the name of the Lord Jesus Christ, giving thanks to God the Father through Him" (Apostolicam Actuositatem).
The temporal natures of our lives on Earth are often derided as evil by some denominations. The Church firmly believes that the temporal make up of our world can be used to positively affect the spiritual affairs of those around us. The Lumen Gentium does a magnificent job of elucidating our vocation as lay apostles:
But the laity, by their very vocation, seek the kingdom of God by engaging in temporal affairs and by ordering them according to the plan of God. They live in the world, that is, in each and in all of the secular professions and occupations. They live in the ordinary circumstances of family and social life, from which the very web of their existence is woven. They are called there by God that by exercising their proper function and led by the spirit of the Gospel they may work for the sanctification of the world from within as a leaven. In this way they may make Christ known to others, especially by the testimony of a life resplendent in faith, hope and charity (Lumen Gentium).
Correspondingly, the Apostolicam Actuositatem says the same: Since the laity, in accordance with their state of life, live in the midst of the world and its concerns, they are called by God to exercise their apostolate in the world like leaven, with the ardor of the spirit of Christ (Apostolicam Actuositatem). Through our actions we partake in the evangelizing mission of the Church. As advocates of the Church, we grow the Body of Christ. Each person that, through Christ, we call to the Church is one more soul who may be united with Christ in the heavenly liturgy through the celebration of the Eucharist.
The temporal order must be renewed in such a way that, without detriment to its own proper laws, it may be brought into conformity with the higher principles of the Christian life and adapted to the shifting circumstances of time, place, and peoples. Preeminent among the works of this type of apostolate is that of Christian social action which the sacred synod desires to see extended to the whole temporal sphere, including culture (Lumen Gentium).