[85] Then the man who is improved by instruction, having an immortal monitor, receives from him a harmonious and imperishable advantage, without suffering any change; but the practiser of virtue is impelled to action by his own inclination alone, and he exercises himself in it, and labours at it in order to change that passion, which is akin to a created being; and even if he attains to perfection, he still, being fatigued, returns to his ancient kind of labour;