Of course, as the famous saying goes "The pen is mightier than the sword" written by Edward Bulwer-Lytton in 1839 for his play Richelieu.
I prefer to replace the pen for word to rhyme with sword. So, I say The word is mightier than the sword. And prefer to say The pen is mightier than the gun.

This topic came up after reading about the elusive Ms. El Aroud, a 48-year-old Belgian,who calls herself a holy warrior of Al Qaeda.

“It’s not my role to set off bombs — that’s ridiculous,” she said in a rare interview. “I have a weapon. It’s to write. It’s to speak out. That’s my jihad. You can do many things with words. Writing is also a bomb.”