Charles Ellicott Commentary Acts 21:29

"For they had before seen with him in the city Trophimus the Ephesian, whom they supposed that Paul had brought into the temple." — Acts 21:29 (ASV)

Trophimus an Ephesian.—See Note on Acts 20:4. His face was naturally familiar to those who had come from the same city. They had seen the two together in the streets, possibly near the entrance of the Temple, and, hatred adding wings to imagination, had taken for granted that St. Paul had brought his companion within the sacred enclosure.