The Christian priesthood, finding the doctrines of Christ levelled to every understanding, and too plain to need explanation, saw in the mysticism of Plato, materials with which they might build up an artificial system, which might, from its indistinctness, admit everlasting controversy, give employment for their order, and introduce it to profit, power and pre-eminence. The doctrines which flowed from the lips of Jesus himself are within the comprehension of a child ; but thousands of volumes have not yet explained the Platonisms engrafted on them; and for this obvious reason, that nonsense can never be explained.

Letter to John Adams (5 July 1814). Published in The Works of Thomas Jefferson in Twelve Volumes, Federal Edition, Paul Leicester Ford, ed., New York: G. P. Putnam's Sons, 1904, Vol. 11, pp. 397–398.