Proverbs 30:32 in the King James Version
If thou hast done foolishly in lifting up thyself, or if thou hast thought evil, lay thine hand upon thy mouth.
Context
31 the greyhound; the male goat; and the king against whom there is no rising up.
32 “If you have done foolishly in lifting up yourself, or if you have thought evil, put your hand over your mouth.
33 For as the churning of milk produces butter, and the wringing of the nose produces blood, so the forcing of wrath produces strife.”