The judges trying him conversed with one another in French so that the Russian defendants would not be privy to their secret discussions regarding the case before them. Unknown to them, Rabbi Luria spoke French fluently and would therefore be in a position to arrange his arguments according to the thinking of the judges. But he felt that this would not be honest and so he put his hands to his ears.
When the judges asked for an explanation of this strange act, the rabbi replied in French that he did not wish to dishonestly overhear their secret discussions. They were so impressed by this extraordinary display of honesty that they decided he was innocent.