“Never bring a knife to a gunfight”

“Never bring a knife to a gunfight” (or “Don’t take a knife to a gunfight”) seems like a quotation from the old west. The film The Untouchables (1987) contained the line: “You wanna know how to get Capone? They pull a knife, you pull a gun. He sends one of yours to the hospital, you send one of his to the morgue. ‘That’s’ the ‘Chicago’ way!”
 
Citations of the “bringing a knife to a gunfight” proverb date from after 1987.
 
   
Urban Dictionary
1. Bringing a knife to a gunfight 
The act of taking an amount of any substance to a gathering which is obviously insufficient.
“You’ve only brought an eighth ? But we’re out all night, you’ll need at least a quarter. That’s like bringing a knife to a gunfight. Fool.”
by Wykey May 20, 2008
 
2.  Bringing a knife to a gunfight
1. The act of purposely or mistakenly bringing less than adequate weaponry to either a military conflict or a poorly organized hardcore show.
2. The process by which a cable router renews a DNS coordinate.
“Shit fool, that s.a. brought a knife to this gunfight, whereas I brought a gun. To this battle between guns primarily. If I were to rephrase this using the present participle, I would say that he is bringing a knife to a gunfight. What a dumbass.”
“Abe Lincoln never brings knives to gunfights. That’s pussy shit.”
by Jedd robble Mar 28, 2006
     
Internet Movie Database
Memorable quotes for
The Untouchables (1987)
Malone: You said you wanted to get Capone. Do you really wanna get him? You see what I’m saying is, what are you prepared to do?
Ness: Anything within the law.
Malone: And *then* what are you prepared to do? If you open the can on these worms you must be prepared to go all the way. Because they’re not gonna give up the fight, until one of you is dead.
Ness: I want to get Capone! I don’t know how to do it.
Malone: You wanna know how to get Capone? They pull a knife, you pull a gun. He sends one of yours to the hospital, you send one of his to the morgue. “That’s” the “Chicago” way! And that’s how you get Capone. Now do you want to do that? Are you ready to do that? I’m offering you a deal. Do you want this deal?
 
12 December 1987, San Frnacisco (CA) Chronicle, “Letters to the Green” pg. D2:
We’re gonna rip into your Bears so bad that nothing will give you solace. The Midway Morons are going to realize they shouldn’t have brought a knife to a gunfight.
 
Google Books
June 1989, Black Belt, pg. 26, col. 2:
Otherwise, you might end up taking a knife to a gunfight, as the joke goes.
 
Google Books
Money:
How to Get It, Keep It, Make It Grow
By Tama McAleese
Hawthorne, NJ: Career Press
1991
Pg. 11:
Never bring a knife to a gunfight
 
Google Books
CopTalk:
Personal and family safety information for your life
By Mark Lambert, Brent Burzycki, and Jim Lambert
Danville, CA: NetCops P.S.I.
1998
Pg. 33:
Moral of that story, “Don’t take a knife to a gunfight”.