Wiktionary
raise one's hand
vb. 1 (context idiomatic English) To volunteer. 2 (context idiomatic English) To dare to question.
Usage examples of "raise one's hand".
The old High Priest of Aminreh died toonot by violence, for one does not raise one's hand against the chosen of the god, but after a year of imprisonment.
He started with this question and this juror because it was an easy warm-up, a soft pitch to show the others how painless it was to raise one's hand and discuss matters.