Dr. King only said part of this:

I mourn the loss of thousands of precious lives, but I will not rejoice in the death of one, not even an enemy. Returning hate for hate multiplies hate, adding deeper darkness to a night already devoid of stars. Darkness cannot drive out darkness: only light can do that. Hate cannot drive out hate: only love can do that.

Bob Cargill tells which part, and explains how the whole thing is relevant to how we got the Apocrypha.