Why did Plato support noble lies by rulers in an ideal society?

In his work The Republic, Plato argued that the rulers of an ideal society must promulgate "noble" lies to foster social harmony among the masses.1

Plato’s support for such deception was rooted in his belief that the moral value of a lie depends on the context in which it is told. He viewed the state as a structure that should promote the "good life" and social order, and he believed that philosopher-statesmen—who possess knowledge of the Forms—could use public power to achieve these moral ends. By employing noble lies, rulers could manage the population and maintain the stability of the state, which Plato considered essential for preventing the corruption and political injustice he observed in his own time.123

While Plato recognized the importance of truth, his political philosophy prioritized the functional harmony of the state, where each class performs its proper role. Consequently, he viewed these strategic deceptions as tools for the elite to guide the citizenry toward a unified and virtuous existence, even if the means involved misleading the public for the greater good.321