Catechism of the Catholic Church

"The Christian faithful are those who, inasmuch as they have been incorporated in Christ through Baptism, have been constituted as the people of God; for this reason, since they have become sharers in Christ's priestly, prophetic, and royal office in their own manner, they are called to exercise the mission which God has entrusted to the Church to fulfill in the world, in accord with the condition proper to each one." (1268-1269, 782-786)