XXe-ras-tus (Erastos, "beloved"): The name occurs three times, each time denoting a companion of Paul.
(1) Erastus was sent with Timothy from Ephesus into Macedonia while Paul remained in Asia for a while. They are designated "two of them that ministered unto him" (Acts 19:22).
(2) "Erastus the treasurer of the city" sent greetings to the Christians in Rome (Rom 16:23). He was apparently an important person in the Corinthian community, and with Gaius probably represented that church in these fraternal relations with the Roman community.
(3) Erastus is one who, in 2 Tim 4:20, "remained at Corinth."
We have no means of discovering whether one or more than one person is meant in these references. A. C. Headlam (HDB, under the word) thinks it improbable that one who held an office implying residence in one locality should have been one of Pauls companions in travel. On the other hand Paul may be designating Erastus (Rom 16:23) by an office he once held, but which he gave up to engage in mission work.
S. F. Hunter