I'm inclined to go with Donna Janelle: What goes round comes around.
Karma is believed by Hindus and a number of other religions - and perhaps even the Christian Religion in that phrase, "As you do to others, so it will be done unto you," or somesuch.
But it refers not only to human intentions. It apparently means that things must BALANCE out or neutralize. We've heard of Ying and Yang, Positive and Negative, Acid and Alkaline, et cetera. Balance is the answer, it seems.
It's up to us as individuals, of course, to determine what those balances are.