Malcolm X expounded on that quote from Goldwater (although Goldwater didn’t originally come up with it):
My reason for believing in extremism—intelligently directed extremism, extremism in defense of liberty, extremism in quest of justice—is because I firmly believe in my heart that the day the black man takes an uncompromising step and realizes he’s within his rights, when his own freedom is being jeopardized, to use any means necessary to bring about his own freedom or put a halt to that injustice, I don’t think he’ll be by himself.