"When the Church comes together in the liturgical assembly to celebrate the Mass, or any other sacrament, her members do not gather simply as a crowd, as an amorphous, undifferentiated group of people. They gather in a variety of ministries and roles. If we are to understand the significance of these ministries and roles, we must begin with Baptism, for only one who through Baptism has been given a share in the priesthood of Christ is capable of participating in the public worship which is the liturgy of the Church. In fact, the Constitution on the Sacred Liturgy of the Second Vatican Council tells us that participation in the liturgy is the right and duty of all the baptized."
- USCCB, Ministries and Roles within the Liturgical Assembly at Mass