2 Timothy 4:20

‘Erastus remained at Corinth: but Trophimus I left at Miletus sick.’

Erastus is mentioned in Acts 19:22 as a co-worker with Timothy, and his whereabouts would thus have been of interest to him. It may be that he had taken up an independent ministry in Corinth as he is not mentioned in the list of lieutenants in 10-12/14. Trophimus was out of action. He was an Ephesian. Compare for his relationship with Paul, Acts 20:4; Acts 21:29. He was one of those who had helped to bring the collection to Jerusalem, and had seemingly been subsequently with Paul. It is interesting that with Paul the wonder worker there he had had to be left at Miletus, clearly very sick. The early days when all were healed have been left behind.