No man can take part in the torture of a human being without having his own moral nature permanently lowered.
 Theodore Roosevelt, State of the Union Address. copy citation

Context

“The members of the white race on the other hand should understand that every lynching represents by just so much a loosening of the bands of civilization; that the spirit of lynching inevitably throws into prominence in the community all the foul and evil creatures who dwell therein. No man can take part in the torture of a human being without having his own moral nature permanently lowered. Every lynching means just so much moral deterioration in all the children who have any knowledge of it, and therefore just so much additional trouble for the next generation of Americans. Let justice be both sure and swift;” source