That's the way I heard it, but the actual quote from English critic Sir Arthur Quiller-Couch in a 1914 essay On the Art of Writing is "Murder your darlings." Often it's that phrase we are most proud of, that character we have fallen in love with that needs to be cut. It's tough because it feels personal, and indeed, it is a loss. But it must be done. Today, self-edit a piece and be brave enough to cut what needs to be cut.