“They must find it hard to take Truth for authority who have so long mistaken Authority for Truth.”
A Retort, from Gerald Massey's Lectures c.1900; often cited as They must find it difficult, those who have taken authority as truth, rather than truth as authority.
Based on a quote of Lucretia Mott, "… my convictions led me to adhere to the sufficiency of the light within us, resting on truth as authority, rather than “taking authority for truth.”", quoted in " Eminent women of the age http://books.google.de/books?id=gGFEDpWYWpwC&pg=PA375" By James Parton et. al., (S.M. Betts & Company, 1868, p375).