Whether there should be different duties or states in the Church?

Objections

Objection 1 : It would seem that there should not be different duties or states in the Church. For distinction is opposed to unity. Now the faithful of Christ are called to unity according to Jn. 17:21,22: "That they . . . may be one in Us . . . as We also are one." Therefore there should not be a distinction of duties and states in the Church.
Objection 2 : Further, nature does not employ many means where one suffices. But the working of grace is much more orderly than the working of nature. Therefore it were more fitting for things pertaining to the operations of grace to be administered by the same persons, so that there would not be a distinction of duties and states in the Church.
Objection 3 : Further, the good of the Church seemingly consists chiefly in peace, according to Ps. 147:3, "Who hath placed peace in thy borders," and 2 Cor. 13:11, "Have peace, and the God of peace . . . shall be with you." Now distinction is a hindrance to peace, for peace would seem to result from likeness, according to Ecclus. 13:19, "Every beast loveth its like," while the Philosopher says (Polit. vii, 5) that "a little difference causes dissension in a state." Therefore it would seem that there ought not to be a distinction of states and duties in the Church.