The Lion in Winter

Katharine Hepburn says this in the 1968 film The Lion in Winter. (I don't know if the same line is in the play on which it was based.)

How clear we make it. Oh, my piglets, we are the origins of war. Not history's forces, nor the times, nor justice, nor the lack of it, nor causes, nor religions, nor ideas, nor kinds of government, nor any other thing. We are the killers. We breed wars. We carry it, like syphilis, inside. Dead bodies rot in field and stream because the living ones are rotten. For the love of God, can't we love one another just a little? That's how peace begins.