Proverbs 30:32
If thou hast done foolishly in lifting up thyself, or if thou hast thought evil, lay thine hand upon thy mouth.
Cross-references
Proverbs 17:28 says even a fool is counted wise when silent, directly paralleling the advice to lay hand on mouth after folly.
Proverbs 26:12 declares that a man wise in his own conceit is worse than a fool, matching the warning against self-exaltation here.
Job 21:5 uses the identical gesture 'lay your hand upon your mouth' for astonishment, mirroring the same action here.
Job 40:4 has Job putting his hand over his mouth in humility before God, the same response to folly here.
Micah 7:16 describes nations laying hand on mouth in shame, the same idiom for silencing oneself after folly.
Romans 3:19 says every mouth is stopped before God—parallel to putting hand on mouth for guilt.
Judges 18:19 commands 'put your hand over your mouth'—the exact idiom used in this proverb.
Job 29:9 describes princes laying hand on mouth in reverence—same gesture as the silencing advice here.