King's genius here lies in rejecting the seductive notion that history moves on its own—that we can simply wait for progress to arrive like a train on schedule. The hard part is naming what "continuous struggle" actually costs: the organizing meetings that run past midnight, the relationships strained by conviction, the small victories that feel hollow against the vastness of what remains broken. When you're negotiating with your employer about fair treatment or pushing back against a friend's casual prejudice, you're enacting this principle—and you'll notice that the moment you stop pushing, the wheels don't keep turning.