Acts 19:22

‘And having sent into Macedonia two of those who ministered to him, Timothy and Erastus, he himself stayed in Asia for a while.'

As a preliminary to this he sent two of his assistants, Timothy and Erastus, to Macedonia, while he remained a little longer at Ephesus. This coming visit might have been intended to be the last that he would make to them (Romans 15:23). One of its purposes was in order to receive the collection which they had been making (1 Corinthians 16:1; 1 Corinthians 2 Corinthians 8-9) in order to take it on to the needy people of Judaea, but Luke clearly intends to pass over this whole visit as briefly and as uninformatively as possible.

This is the first mention that we have of Erastus (compare 2 Timothy 4:20), which was a fairly common name. It is a reminder that Paul's missionary parties may always have been larger than we might have gathered from Acts. Luke, for example, never tells us about the presence of Titus, but judging by Paul's letters he must often have been with Paul.