Acts 19:33

‘And they brought Alexander out of the crowd, the Jews putting him forward. And Alexander beckoned with the hand, and would have made a defence to the people.'

Then a man called Alexander was put forward by the Jews, who would not be favourable to Paul. This might well have been because sinister rumours were spreading around that Paul was a Jew, and they were afraid that it would arouse feelings of anti-Semitism, something that they knew could only too easily be aroused. They wanted to ensure that the Jews did not share the blame for Paul's activities. Alexander then beckoned with his hand in order to obtain a hearing, and explain things to the assembly, which would probably not have boded Paul's companions any good.