Acts 6:4

We will give ourselves continually to prayer, and to the ministry of the word. — Literally, We will persevere in... These formed the true work of the Apostles, as afterwards of the bishops or elders of the Church. “Prayer” includes the public worship of the Church in all its various developments, as well as private prayer and intercession; the “ministry of the word,” all forms of teaching.

It is to be noted that the men thus appointed are never called “deacons” in the New Testament. When they are referred to again it is as “the Seven” (Acts 21:8), as though they were a distinct and peculiar body. Their functions were, of course, in some degree, analogous to those of the “deacons” of the Pastoral Epistles and the later organisation of the Church; but these, as we have seen, had their prototypes in the “young men,” as contrasted with “elders,” in Acts 5:6; Acts 5:10; and the Seven were probably appointed, so to speak, as archdeacons, to superintend and guide them. In some churches, as at Rome, the number of deacons was fixed at seven, in conformity with this precedent (so also at the Council of Neo-Cæsarea, Can. 14, A.D. 314), and they were considered, when the bishop came to be distinguished from the elders, as acting more immediately under the direction of the former, helping him in the details of his office.