“The rarest of all human qualities is consistency.”

Source: Jeremy Bentham, Introduction to the Principles of Morals and Legislation, Chapter 1
Context: Not that there is or ever has been that human creature at breathing, however stupid or perverse, who has not on many, perhaps on most occasions of his life, deferred to it. By the natural constitution of the human frame, on most occasions of their lives men in general embrace this principle, without thinking of it: if not for the ordering of their own actions, yet for the trying of their own actions, as well as of those of other men. There have been, at the same time, not many perhaps, even of the most intelligent, who have been disposed to embrace it purely and without reserve. There are even few who have not taken some occasion or other to quarrel with it, either on account of their not understanding always how to apply it, or on account of some prejudice or other which they were afraid to examine into, or could not bear to part with. For such is the stuff that man is made of: in principle and in practice, in a right track and in a wrong one, the rarest of all human qualities is consistency.