A.T. Robertson Commentary Romans 16:1

"I commend unto you Phoebe our sister, who is a servant of the church that is at Cenchreae:" — Romans 16:1 (ASV)

I commend (συνιστημ). The regular word for letters of commendation as in 2 Corinthians 3:1 (συστατικων επιστολων). 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 (Φοιβη) means bright or radiant.

Sister (αδελφην). In Christ, not in the flesh.

Who is a servant of the church (ουσαν διακονον της εκκλησιας). The etymology of διακονος 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; 1 Timothy 3:8–13. In favour of the technical sense of "deacon" or "deaconess" is the addition of "της εκκλησιας" (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 1 Timothy 3:8–13 Paul has a discussion of γυναικας (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 1 Timothy 5:9f.