<P> Arnaud Amalric (Latin: Arnoldus Amalricus; died 1225) was a Cistercian abbot who played a prominent role in the Albigensian Crusade . He is remembered for purportedly advising a soldier who was worried about killing orthodox Catholics instead of just heretic Cathars, prior to the sack of Béziers, to simply kill everyone, as God would sort it all out later . </P> <P> He was abbot of Poblet in Catalonia from 1196 to 1198, then of Grandselve from 1198 to 1202 . He then became the seventeenth abbot of Cîteaux (until 1212). </P>

Where did the saying kill them all let god sort them out