An illustration of the fable from Kalilah and Dimna

A turtle carries a stranded scorpion across a river. The scorpion stings the turtle who demands indignantly: "My nature is to be helpful. I have helped you and now you sting me." "My friend," says the scorpion, "your nature is to be helpful. Mine is to sting. Why do you seek to transform your nature into a virtue and mine into villainy? ~Rumi