Chapter 75 — On the different kinds of order

A power directed to a principal effect naturally has lesser powers administering to it. This may be clearly seen in the arts: the arts which dispose the material are subservient to the art which introduces the artificial form, and the art that introduces the artificial form is subservient to the art which is concerned with the end of the artifact. And again, the art that is concerned with an anterior end is subservient to the art that is concerned with the ultimate end. Thus the art of wood-cutting serves the ship-building art; the latter serves the art of sailing; and this latter serves the art of commerce or war or the like, insofar as sailing may be directed to various ends.

Since, then, the power of order is directed chiefly to the consecration of Christ’s body, and to its distribution to the faithful, and likewise to the cleansing of the faithful from their sins, there is need for a principal order whose power extends chiefly to these things, and this is the priesthood. There is also a need for other orders that serve it by preparing the matter in one way or another, and these are the orders of the lower ministers. Accordingly, since the priestly power, as we have stated, (Ch. 74.) extends to two things (namely, the consecration of Christ’s body and the preparation of the faithful by absolving them from their sins, that they may be worthy to receive the Eucharist), it follows that the lower orders should minister to the priestly order either in both or in one of these things. And it is clear that among the lower orders, the higher is the one that serves the priestly order in more ways, or in a higher way.

The lowest orders, then, serve the priestly order only in the preparation of the people: the porter by excluding unbelievers from the assembly of the faithful; the lectors by instructing catechumens in the rudiments of the faith (hence the Old Testament Scriptures are committed to them to read); the exorcists by cleansing those who are already instructed, if in any way they be hindered by the devil from receiving the sacraments.

The higher orders serve the priestly order both in the preparation of the people and in the celebration of the sacrament. Acolytes exercise their ministry over the non-sacred vessels, in which the matter of the sacrament is prepared; therefore, the cruets are delivered to them at their ordination. Subdeacons exercise their ministry over the sacred vessels, and the preparation of the matter before consecration. Deacons exercise a ministry over the already consecrated matter, inasmuch as they distribute Christ’s blood to the faithful. Therefore, these three—the priesthood, diaconate, and sub-diaconate—are called sacred orders because they confer a ministry over sacred things. These higher orders serve also in the preparation of the people: hence deacons are entrusted with the proclamation of the Gospel teaching; subdeacons, with the teaching of the apostles; while the acolytes serve by conducing to the solemnity of that teaching by bearing lighted candles, and in other like ministrations.