Acts 13:16

‘And Paul stood up, and beckoning with the hand said, “Men of Israel, and you who fear God, listen.” '

Often the address would be given seated, especially if it was an exposition of the passage read. But Paul's rising would not be seen as unusual, and regularly occurred elsewhere. It would be an indication of the emphasis that he wanted to put on his message, something that he also confirmed with a gesture of his hand, and his strong plea to them to take notice (which he will also repeat at the end). It possibly also indicated that it was not just to be an exposition of the reading.

‘Men of Israel, and you who fear God.' Both Jews, and Gentile God-fearers, were present and he was equally addressing both.