Many sources quote Thomas Jefferson as saying, "No duty the Executive had to perform was so trying as to put the right man in the right place." This is in fact a paraphrase of Jefferson's actual statement, in an 1801 letter to the merchants of New Haven, Connecticut:
"Of the various Executive duties, no one excites more anxious concern than that of placing the interests of our fellow citizens in the hands of honest men, with understandings sufficient for their station. no duty, at the same time, is more difficult to fulfill."
The source of the above-mentioned paraphrase, which has been mistaken for a direct quotation, is John B. McMaster's History of the People of the United States, which describes Jefferson's statement as follows:
"Jefferson's reply to the remonstrance was a discussion of the tenure of office, and soon forgotten. But one sentence will undoubtedly be remembered till our Republic ceases to exist. No duty the Executive had to perform was so trying, he observed, as to put the right man in the right place."