On the Validity of the Biblical Text
But the whole history of these books is so defective and doubtful that it seems vain to attempt minute inquiry into it: and such tricks have been plaid with their text, and with the texts of other books relating to them, that we have a right, from that cause, to entertain much doubt what parts of them are genuine. In the New testament there is internal evidence that parts of it have proceeded from an extraordinary man; and that other parts are of the fabric of very inferior minds. It is as easy to separate those parts, as to pick out diamonds from dunghills. The matter of the first was such as would be preserved in the memory of the hearers, and handed on by tradition for a long time; the latter such stuff as might be gathered up, for imbedding it, any where, and at any time.
In a letter to John Adams, 24 January 1814. The Adams-Jefferson Letters, p. 421.