Before Mad Dog Mattis made that quote he could have at least given credit to Malcom X.
Which quote are you referring to? I am unaware of either being credited to Malcom X. (sic)
However, Malcolm X is credited with saying this: "Be peaceful, be courteous, obey the law, respect everyone; but if someone puts his hand on you, send him to the cemetery."

Worded differently but the intent of it is pretty much the same.
Other quotes credited to General Mattis:
http://freebeacon.com/the-best-from-mad-dog-mattis/