It used to be commonly thought that only priests and religious have vocations; laity have careers where they basically do their own thing within the bounds of basic morality.
This was a notion that represented a gross impoverishment of the mission of the Church. It not only relegated the laity to the status of ecclesiastical hangers-on, but also underestimated the action of the Holy Spirit in each person.
In this matter at least, the Second Vatican Council turned things upside down. No longer was the Church understood as primarily a pyramidal structure comparable to medieval feudalism. Vatican II re-envisioned the Church as a communion of the faithful, the Body of Christ, the People of God.
The Church has a hierarchical structure to be sure, but the ordained ministry is now conceived of as at the service of the communion. The laity share through their Baptism in Christ's offices of priest, prophet and king. This sharing in those offices differs in essence from the manner in which the ordained clergy participate. Nevertheless, the laity are now clearly seen as having a crucial role in carrying out Christ's mission.
That mission, as Vatican II stated, is to permeate the secular world with the spirit of the Gospel.
Pope John Paul II pushed this understanding of the laity even further. In his 1988 apostolic letter, Christifideles Laici (CL), he said that every baptized person has a unique personal vocation (n. 58). Each person is called to "an ever-clearer discovery of one's vocation and the ever-greater willingness to live it."
As a Church, we are called to evangelize and transform the world. Within the Church, each person has received gifts, "whether they be exceptional and great or simple and ordinary" that we are called to use to build up the Church or nurture the well-being of humanity (CL 24).
These gifts complement each other; they are part of God's plan of salvation and the Holy Spirit gives them to us.
You cannot be a Christian and do your own thing. You have been anointed to bear fruit through your life - in your work, your family and your recreation and other activities. "Bearing fruit is an essential demand of life in Christ and life in the Church. The person who does not bear fruit does not remain in communion" (CL 32).
We cannot see our careers or any of our undertakings as isolated individual activities. They are the places in which acts the Body of Christ of which we are the hands and feet.
How does one bear fruit? By cooperating with the Spirit of God. We are called to discern God's will for our lives and to carry it out. That means we are called to live lives of constant prayer and continuing education in Scripture and the teaching of the Church. We are called to oneness with Christ in all things and at all times.
Our diverse natural gifts as well as the milieu in which we live our lives are not ours alone. They are part of the riches of the Church. Only we can bring those unique riches to the altar. Only we can bring the altar to situations that are often far removed from the reach of the organized Church. If we don't bring Christ to those situations, he won't arrive and his mission will be stymied in that area.
Pope John Paul gave us a wonderful vision of lay people living out their unique vocations and how that can affect the world:
"The eyes of faith behold a wonderful scene: that of a countless number of lay people, both women and men, busy at work in their daily life and activity, oftentimes far from view and quite unacclaimed by the world, unknown to the world's great personages but nonetheless looked upon in love by the Father, untiring labourers who work in the Lord's vineyard.
"Confident and steadfast through the power of God's grace, these are the humble yet great builders of the kingdom of God in history" (CL 17).
This is Christ in action in our world. When we are united with the Spirit-filled Church, we bear abundant fruit that will last. That fruit may not even be observed by an unbelieving world. But it is the fruit that nourishes the world and witnesses to the presence of the Holy Spirit.