General principles of Vatican II
The church is a mystery, or sacrament, and not primarily a means of salvation.
The church is the whole People of God, not just the hierarchy.
The whole People of God participates in the mission of Christ, and not just in the mission of the hierarchy.
The mission of the church includes service to those in need, and not just the preaching of the Gospel or the celebration of the sacraments.
The church is truly present at the local level as well as at the universal level. A diocese or parish is not just an administrative division of the church universal.