What is the difference between verbal irony and sarcasm?

Answer 1

I'd tell you but then I'd have to kill you. : )

(In case you don't get it, that is an example of sarcastic irony)

Answer 2

Irony is not necessarily hostile toward someone.
Here is irony. A church full of worshipers fell down on them in an earthquake.
Sarcasm is a form of hostile statement. Based on his admittance to Yale, you know George Bush must have had a wealthy father.

Answer 3

Irony is something that happens, sarcasm is making an abusive comment about something