Philo Judaeus Quod Deterius Potiori Insidiari Soleat 102

[102] Nor does it follow that, because for the sake of the perpetuation of your race you have been endowed with the powers of generation, you ought to pursue pollutions and adulteries and other impure connections; but only such as, in a legitimate manner, engender and propagate the race of mankind. Nor, because you have been made endowed with a mouth and a tongue and the organs of speech, ought you to say everything and to reveal what ought not to be spoken, for there are times when to hold one’s peace is useful. And, in my opinion, those who have learnt to speak have also learnt to be silent, the same capacity teaching a man both lines of conduct. But those men who relate what they ought not, do not display the faculty of eloquence, but the weakness of their faculty of silence.