From elsewhere:

'The phrase, "Kill them all and let God sort them out," is attributed to Dominic Guzman. He's the founder of the Dominican order of priests. He and an armed troop of heretic hunters had come across a town that was supposed to contain a number of heretics. Guzman gave orders to kill everyone in town. When one of his subordinates told him that there were probably a lot of good Christians mixed up with the heretics what Guzman actually said was, "Kill them all and God will know his own."'



Bunch of damned plagiarists. The only credit they deserve is for recognizing a good line when they heard it.