II.8. Deacons.
[...] Without the deacons, a priest has the name but he does not have the office. (4) For as in the case of priest, consecration is of the sacrament, so in the minister, dispensation is of the sacrament. The priest is commanded to pray, the deacon to sing psalms. The priest sanctifies the offerings; the deacon dispenses the things sanctified. Also it is not permitted for the priests, on account of presumption, to take the chalice from the table of the Lord, unless it has been handed to them by the deacon. Levites place the offerings on the altar; Levites prepare the table of the Lord; Levites cover the ark of the testament. For not all see the high things of the mysteries which are covered by the Levites, lest they who ought not to see, see, and those who are not able to serve, lay hold of them. [...]
(trans. Knoebel 2008: 79, 80)