… is from page 16 of Hayek’s 1948 collection, Individualism and Economic Order; in particular, it is from Hayek’s deep and profound 1945 lecture “Individualism: True and False”:
There is all the difference in the world between treating people equally and attempting to make them equal. While the first is the condition of a free society, the second means, as De Tocqueville described it, “a new form of servitude.”