“I have read their platform, and though I think there are some unsound places in it, I can stand upon it pretty well. But I see nothing in it both new and valuable. "What is valuable is not new, and what is new is not valuable."”

From The Edinburgh Review, The Work of Thomas Young (c. 1802).

1850s, Address before the Wisconsin State Agricultural Society (1859)
Context: I suppose, however, I shall not be mistaken, in assuming as a fact, that the people of Wisconsin prefer free labor, with its natural companion, education. This leads to the further reflection, that no other human occupation opens so wide a field for the profitable and agreeable combination of labor with cultivated thought, as agriculture. I know of nothing so pleasant to the mind, as the discovery of anything which is at once new and valuable — nothing which so lightens and sweetens toil, as the hopeful pursuit of such discovery. And how vast, and how varied a field is agriculture, for such discovery. The mind, already trained to thought, in the country school, or higher school, cannot fail to find there an exhaustless source of profitable enjoyment.

Last recorded words, as quoted in The Encyclopædia Britannica (1910)

The Genetic Revolution—Great Promise With Growing Concern, Awake! magazine, July 22, 1989.

Conversations with Einstein by Alexander Moszkowski (1971), p. 69 http://books.google.com/books?id=_D3wAAAAIAAJ&q=%22first+lessons+should+contain+nothing+but+what%22#search_anchor. This is just Moszkowski's English translation of a statement he attributed to Einstein in his 1922 book Einstein, Einblicke in seine Gedankenwelt, p. 77 http://books.google.com/books?id=6zHPAAAAMAAJ&pg=PA77#v=onepage&q&f=false: "Was die Physik betrifft, fuhr Einstein fort, so darf für den ersten Unterricht gar nichts in Frage kommen, als das Experimentelle, anschaulich-Interessante. Ein hübsches Experiment ist schon an sich oft wertvoller, als zwanzig in der Gedankenretorte entwickelte Formeln." As Moszkowski makes clear in the original German text, this "quotation" is a paraphrasing of his conversation with Einstein.
Attributed in posthumous publications

Life lessons from Narayana Murthy (2013)

Source: Fantastic Mr. Fox

Source: Calculating God (2000), Chapter 7 (p. 77)

Source: Q A: Slumdog Millionaire