How Do I Know E=mc2

Since I demand sufficient objective evidence for what I think is true, here is the question:
I assume, from reading your book the OTF, that you believe that E=mc2. (Perhaps you would say that you do not "believe" that E=mc2; rather, you "know" that E=mc2. Either way; I won't quibble. At least not for now.) The initial question that I have for you is: How do you believe (or, if you insist, know) that E=mc2? Not why, but how? What is the process by which you John Loftus have arrived at the belief (knowledge) that E=mc2?
*Sheesh* Right now I have other things to do than waste it on this drivel. Maybe others can help me out here. [FYI: I did a master's degree research paper on the theory of general relativity.] Here we see another science denier for Jesus.