The Book had in a high degree excited us to self-activity, which is the best effect of any book.

Thomas Carlyle (1795–1881) Scottish essayist and historian

Sartor Resartus, Book 1, ch. 4 (1834)
    (Source)

This passage first appeared in Fraser's Magazine for Town and Country, Vol. 8, No. 47 (1833-11).

This was reorganized and polished in the later 19th Century into how it was widely disseminated (in quotation books, e.g., James Wood (ed.), Dictionary of Quotations from Ancient and Modern, English and Foreign Sources (1893)), and how today it is usually presented:

The best effect of any book is that it excites the reader to self-activity.