Acts 20:14

And when he met us at Assos, we took him in, and came to Mitylene. And sailing from thence, we came the following day over against Chios; and the next day we touched at Samos; ... and the day after we came to Miletus. For Paul had determined to sail past Ephesus, that he might not have to spend time in Asia; for he was hastening, if it were possible for him, to be at Jerusalem the day of Pentecost.

The journey to Jerusalem by Paul and his company was made in a trading ship stopping at numerous places along the coast of the northeast Mediterranean and southwest coast of Asia Minor. The record here is obviously from the log which Luke evidently kept of the voyage. Paul did not wish to visit Ephesus, due to lack of time, and the certainty that he would be detained if he went there; but when he learned how long the ship would be at Miletus, which was only about thirty miles from Ephesus, he sent a messenger and invited the Ephesian elders to meet him there. Apparently, Luke's giving the details of this voyage from Troas to Miletus was intended as background for that meeting.

The day of Pentecost ... Paul's desire to be at Jerusalem then was due to the gathering in Jerusalem on such an occasion of so many from so many different places.