Vincent's NT Word Studies
1. I commend (sunisthmi). See on ch. iii. 5.Phoebe. The bearer of the epistle. The word means bright. In classical Greek an epithet of Artemis (Diana) the sister of Phoebus Apollo.
Servant (diakonon). The word may be either masculine or feminine. Commonly explained as deaconess. The term diakonissa deaconess is found only in ecclesiastical Greek. The "Apostolical Constitutions" 70 distinguish deaconesses from widows and virgins, prescribe their duties, and a form for their ordination. Pliny the younger, about A.D. 104, appears to refer to them in his letter to Trajan, in which he speaks of the torture of two maids who were called minestrae (female ministers). The office seems to have been confined mainly to widows, though virgins were not absolutely excluded. Their duties were to take care of the sick and poor, to minister to martyrs and confessors in prison, to instruct catechumens, to assist at the baptism of women, and to exercise a general supervision over the female church-members. Tryphaena, Tryphosa, and Persis (ver. 12) may have belonged to this class. See on 1 Tim. v. 3-16.
Conybeare ("Life and Epistles of St. Paul") assumes that Phoebe was a widow, on the ground that she could not, according to Greek manners, have been mentioned as acting in the independent manner described, either if her husband had been living or she had been unmarried. Renan says: "Phoebe carried under the folds of her robe the whole future of Christian theology."
Cenchrea. More correctly, Cenchreae. Compare Acts xviii. 18 Corinth, from which the epistle was sent, was situated on an isthmus, and had three ports, Cenchreae on the east side, and Lechaeum on the west of the isthmus, with Schoenus, a smaller port, also on the eastern side, at the narrowest point of the isthmus. Cenchreae was nine miles from Corinth. It was a thriving town, commanding a large trade with Alexandria, Antioch, Ephesus, Thessalonica, and the other cities of the Aegean. It contained temples of Venus, Aesculapius, and Isis. The church there was perhaps a branch of that at Corinth.
Robertson's NT Word Studies
16:1 {I commend} (sunistemi). The regular word for letters of commendation as in #2Co 3:1 (sustatikwn epistolwn). See also #Ro 3:5. So here verses #1,2 constitute Paul's recommendation of Phoebe, the bearer of the epistle. Nothing else is known of her, though her name (Phoib) means bright or radiant. {Sister} (adelphn). In Christ, not in the flesh. {Who is a servant of the church} (ousan diakonon tes ekklesias). The etymology of diakonos we have had repeatedly. The only question here is whether it is used in a general sense or in a technical sense as in #Php 1:1; 1Ti 3:8-13. In favor of the technical sense of "deacon" or "deaconess" is the addition of "ts ekklsias" (of the church). In some sense Phoebe was a servant or minister of the church in Cenchreae. Besides, right in the midst of the discussion in #1Ti 3:8-13 Paul has a discussion of gunaikas (verse #11) either as women as deaconesses or as the wives of deacons (less likely though possible). The _Apostolic Constitutions_ has numerous allusions to deaconesses. The strict separation of the sexes made something like deaconesses necessary for baptism, visiting the women, etc. Cenchreae, as the eastern port of Corinth, called for much service of this kind. Whether the deaconesses were a separate organization on a par with the deacons we do not know nor whether they were the widows alluded to in #1Ti 5:9f.