Fencing student cliche: "the pointy end goes in the other guy"

Again from Game of Thrones, the young lady makes the “pointy end goes in the other guy” remark. I remember it from Zorro as well (and Sir Anthony Hopkins’ perfect reply). Is there an original source for this wonderfully poignant line?

Zorro is the first time I heard it, and none of my fencing friends back in Minnesota ever talked about it being ripped off from anything.

Variant on “Firefly”:
Does he know how to fight with a sword?
I think he knows which end to hold

Brian