“Some one, I think it was Isaac Disraeli, said that he who did not make himself acquainted with the best thoughts of the greatest writers would one day be mortified to observe that his best thoughts are their indifferent ones, and it is from the great books that have stood the test of time that we shall get, not only the most lasting pleasure, but a standard by which to measure our own thoughts, the thoughts of others, and the excellence of the literature of our own day.”

Preface.
The Works of Mr. Alexander Pope (1717)
Context: I would not be like those Authors, who forgive themselves some particular lines for the sake of a whole Poem, and vice versa a whole Poem for the sake of some particular lines. I believe no one qualification is so likely to make a good writer, as the power of rejecting his own thoughts.

Signs of Change (1888), Useful Work versus Useless Toil

Marginalia http://www.easylit.com/poe/comtext/prose/margin.shtml (November 1844)

Preface
Sylvie and Bruno (1889)
Context: I believe this thought, of the possibility of death — if calmly realised, and steadily faced would be one of the best possible tests as to our going to any scene of amusement being right or wrong. If the thought of sudden death acquires, for you, a special horror when imagined as happening in a theatre, then be very sure the theatre is harmful for you, however harmless it may be for others; and that you are incurring a deadly peril in going. Be sure the safest rule is that we should not dare to live in any scene in which we dare not die.
But, once realise what the true object is in life — that it is not pleasure, not knowledge, not even fame itself, 'that last infirmity of noble minds' — but that it is the development of character, the rising to a higher, nobler, purer standard, the building-up of the perfect Man — and then, so long as we feel that this is going on, and will (we trust) go on for evermore, death has for us no terror; it is not a shadow, but a light; not an end, but a beginning!

Source: Culture and Anarchy (1869), Ch. I, Sweetness and Light

"Self-Culture", an address in Boston (September 1838) http://www.americanunitarian.org/selfculture.htm
Context: I have insisted on our own activity as essential to our progress; but we were not made to live or advance alone. Society is as needful to us as air or food. A child doomed to utter loneliness, growing up without sight or sound of human beings, would not put forth equal power with many brutes; and a man, never brought into contact with minds superior to his own, will probably run one and the same dull round of thought and action to the end of llfe.
It is chiefly through books that we enjoy intercourse with superior minds, and these invaluable means of communication are in the reach of all. In the best books great men talk to us, give us their most precious thoughts, and pour their souls into ours. God be thanked for books. They are the voices of the distant and the dead, and make us heirs of the spiritual life of past ages. Books are true levelers. They give to all, who will faithfully use them, the society, the spiritual presence, of the best and greatest of our race.

Source: The Meaning of God in Human Experience (1912), Ch. XIV : The Need of an Absolute, p. 198.