… is from pages 160-161 of the 2007 Definitive Edition (Bruce Caldwell, ed.) of F.A. Hayek’s classic 1944 volume, The Road to Serfdom:
It seems to be almost a law of human nature that it is easier for people to agree on a negative program – on the hatred of an enemy, on the envy of those better off – than on any positive task. The contrast between the “we” and the “they,” the common fight against those outside the group, seems to be an essential ingredient in any creed which will solidly knit together a group for common action.