Acts 19:22

22. Sent… two To prepare his way in the Churches for his visit, he sends, about the Passover of his third year in Ephesus, two harbingers, Timothy and Erastus, purposing, on account of the great and effectual door opened in Ephesus, to remain himself fifty weeks longer, namely, until the ensuing Pentecost. For his own account of these facts see 1 Corinthians 16:5-10, written to the Corinthians from Ephesus during this interval of fifty weeks. Erastus was probably the chamberlain of Corinth, whither he is now going, and is subsequently honourably saluted in Paul’s second letter to Timothy. (Romans 16:23; 2 Timothy 4:6.)

From Ephesus at this time was sent PAUL’S THIRD LETTER, THE FIRST EPISTLE TO THE CORINTHIANS. (A.D. 57.)