If once a man indulges ...

If once a man indulges himself in murder, very soon he comes to think little of robbing; and from robbing he comes next to drinking and Sabbath-breaking, and from that to incivility and procrastination.
If once a man indulges himself in murder, very soon he comes to think little of robbing; and from robbing he comes next to drinking and Sabbath-breaking, and from that to incivility and procrastination.
 Thomas de Quincey

More phrases

All the great things are simple, and many can be expressed in a single word: freedom, justice, honor, duty, mercy, hope.
I know but one freedom and that is the freedom of the mind.
 Antoine de Saint-Exupéry
Freedom is not worth having if it does not connote freedom to err.
The amount of happiness that you have depends on the amount of freedom you have in your heart.
 Thích Nhất Hạnh
Without freedom of thought, there can be no such thing as wisdom - and no such thing as public liberty without freedom of speech.

Quotes from the same author

The peace of nature and of the innocent creatures of god seems to be secure and deep, only so long as the presence of man and his restless and unquiet spirit are not there to trouble its sanctity.
 Thomas de Quincey
Under our present enormous accumulation of books, I do affirm that a most miserable distraction of choice must be very generally incident to the times; that the symptoms of it are in fact very prevalent, and that one of the chief symptoms is an enormous 'gluttonism' for books.
 Thomas de Quincey
Flowers... that are so pathetic in their beauty, frail as the clouds, and in their coloring as gorgeous as the heavens, had through thousands of years been the heritage of children - honored as the jewelry of God only by them - when suddenly the voice of Christianity, counter-signing the voice of infancy, raised them to a grandeur transcending the Hebrew throne, although founded by God himself, and pronounced Solomon in all his glory not to be arrayed like one of these.
 Thomas de Quincey
There is first the literature of knowledge, and secondly, the literature of power. The function of the first is--to teach; the function of the second is--to move, the first is a rudder, the second an oar or a sail. The first speaks to the mere discursive understanding; the second speaks ultimately, it may happen, to the higher understanding or reason, but always through affections of pleasure and sympathy.
 Thomas de Quincey
There is first the literature of KNOWLEDGE, and secondly, the literature of POWER. The function of the first is -- to teach; the function of the second is -- to move.
 Thomas de Quincey