This is what he said for those who do not know:

"I want to fight Brock Lesnar. I hate who he is as a person. I want to break his neck in the ring. I want him to be the first person that dies to Octagon-related injuries.”—Frank Mir, WXDX Radio

While his comments were unprofessional and not well thought out I could personally care less what he said. I do think it was smart of Mir to make a public apology for his remarks though.