he shall be the last of all and the servant of all.”
-- Mk 9:30-37
The very differences which the Lord has willed to put between the members of his body serve its unity and mission. For "in the Church there is diversity of ministry but unity of mission. To the apostles and their successors Christ has entrusted the office of teaching, sanctifying and governing in his name and by his power. But 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." Finally, "from both groups [hierarchy and laity] there exist Christian faithful 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