If you have been foolish in exalting yourself, or if you have plotted evil, put your hand on your mouth (Proverbs 30:32).
Pride is a very bad thing when it goes no farther than the thoughts, but it is still worse when it swells and overflows by the lips. If any proud or injurious thought come into our minds, it ought to be immediately checked and suppressed. To discover it by our words is to declare our sin as Sodom, to give indulgence to those passions that ought to be mortified, and to add iniquity to iniquity. Besides, if we do not lay our hand upon our mouth, we shall rouse the pride of other men, and kindle up rage and strife that will not be easily allayed; and thus we shall be accountable not only for our own sin, which is heavy enough of itself, but likewise for those iniquities that we occasion in others, by the temptations which we throw in their way.