Lay thine hand upon thy mouth - The act expresses the silence of humiliation and repentance after the sin has been committed, and that of self-restraint, which checks the haughty or malignant thought before it has passed even into words.
Related Commentaries of Proverbs 30:32
Proverbs 30:32
32 If thou hast done foolishly in lifting up thyself, or if thou hast thought evil, lay thine hand upon thy mouth.