Some more!
Someone already mentioned Judas Priest's The Sentinel, but there's also this line from The Ripper:"I'm sly and I'm shameless, nocturnal and nameless, except for The Ripper, or if you like, Jack the Knife"
Ray Wiley Hubbard-Wanna Rock and Roll:"The dead man's name was Louis DuPris, I pushed a little button on my knife, walked up to 'em said hello boys and girls, have you enjoyed your lives?"
Savatage-Sammy and Tex:
"Seemed things were going aright...
Till Sammy pulled a knife
If you wanna to cut the cards,
Sammy's gonna up the odds!
Then everything was quiet
A street after the riot
And the silence hung like death
And Tex he wasn't breathing
His body lay there bleeding
A knife inside his chest"
With these the titles speak for themselves:
Twisted Sister-Like a Knife in the Back
Falconer-Jack the Knife
Dream Theater-Raise the Knife
Cirith Ungol-Edge of a Knife
Twisted Tower Dire-The Dagger's Blade
As a metalhead, I could name songs referencing swords all day long, as tons of bands I listen to sing about ancient history and/or fantasy, so I'm trying to limit it to just references to knives specifically. Also, I'm sure Cannibal Corpse mentions knives in some of their material, but I don't like the band so I can't give specifics.