The kind lie that saved a captive
A captive about to be executed curses the king in a language the king cannot understand. A merciful vizier translates the curse as a Quranic verse praising those who restrain anger and forgive, so the king spares him, and a rival vizier then reveals what the man actually said. The king answers that the first vizier's lie, told to do good, pleased him more than the second's truth, told to do harm, which gives the book's line that a well-meant falsehood is better than a truth that stirs up mischief.