כל מי שנעשה רחמן במקום אכזרי סוף שנעשה אכזרי במקום רחמן
All who are made to be compassionate in the place of the cruel
In the end are made to be cruel in the place of the compassionate
Qohelet Raba, 7:16
The more colloquial version is, “If you are kind to the cruel, you will end up being cruel to the kind.”
Who would have guessed where this aphorism came from? //Mark
(h/t Contentious Centrist)