Dueling with Words

There is an old proverb that equates rash words with sword thrusts. In modern-day terms, we call it a filter (or lack thereof) and often it's used jokingly or flippantly (I once knew a girl who would always say, "I have no filter!", as if that excused her poorly-timed comments and lack of tact.) You've probably been on both sides of that equation, either speaking without thinking, or feeling the backlash of someone's thoughtless words. There's a reason the wise men of a bygone age made the analogy between words and swords--if you mishandle them, they can cut.

Sometimes you mishandle the sword out of an honest mistake, and end up cutting someone accidentally. I mishandled my words yesterday, in the worst kind of way, when you mean something but it comes out all wrong and ends up sounding like something else. I was lounging in a friend's living room, watching a TV show. She offered me half of the Nut Roll she was eating, but because I wasn't hungry, I said no thank you, and had the grace to add, "It will turn you into a nutroll."
What I was thinking was something along the lines of going crazy (like a nutter) because we were watching a show that contained nutcases. Instead I ended up implying that she was getting fat.

There's a reason for the cliche Stick-Your-Foot-In-Your-Mouth. I was so mortified. Instead of sheathing my sword and apologizing, I dug myself deeper into that shameful hole by not saying anything. I didn't know how to explain what I was thinking and where it came out wrong. She laughed lightly, because that's what you do when you've been cut and don't want to show that you're bleeding.
The exchange was there and gone, and in my confusion and floundering I tried to glaze over the comment by changing the subject. It will all be forgotten in a moment, I thought to myself. 

Yet I knew better. I'm a female, too, and we're hypersensitive to any reference to appearance. A thrust like that would leave a tiny scar for years to come.
Why do we do that?
Why do we cut people with our words, intentionally or not, and then try to save our own face?
What the world would be like if we all had command of our tongues...
There's another proverb that is more encouraging and a good reminder to live by:

Do not let any unwholesome talk come out of your mouth, but only what is helpful for building others up, according to their needs, that it may give grace to those who hear.