Huh, well that's a new take on it

A pen can write poetry and you bet your sweet ass I'll stab you with that same pen.

What if you filled a really fine fountain pen with some kind of poison then stabbed someone, that would be pretty cool

I dunno, I stabbed my friend with a sword and now he writes damn fine poetry

Yeeees, but the man who knows how to use a pen has a thousand swords.

Why hasn't anyone made a pen sword?

Pen can make people use the sword

*mighty is the mind that can do both and decide when, mighty is the hand that can.

The pen controls the sword so

Usually there's not a lot of people who can use both the pen and the sword to perfection, so this doesn't make sense. The one using the pen with virtuosity can manipulate the ones with the swords to do almost whatever s/he wants, while no army of swords has ever buried an elaborated idea transported thru words, hence that proverb.

Guns win battles