Sirach 20:5-7

Revised Standard Version

⁵ There is one who by keeping silent is found wise,
    while another is detested for being too talkative.
⁶ There is one who keeps silent because he has no answer,
    while another keeps silent because he knows when to speak.
⁷ A wise man will be silent until the right moment,
    but a braggart and fool goes beyond the right moment.