Wise is not to speak, but to know when to speak. To know very well why you keep quiet and what to speak.
Take heed before you speak, to answer what is required and what is necessary.
Be aware of your own ignorance and in this way you will avoid many troubles. Because that one who pretends that he knows many things causes a lot of troubles for himself. Since no one knows anything (see Corinthians 8,2). And to blame yourself as if you were below any man is above all goodness. This makes us be closer to God.