Quote 1
"'To the very end,' I said, shakily. 'I heard his very last words. . . .' I stopped in a fright.
'Repeat them,' she murmured in a heart-broken tone. 'I want–I want–something – something – to – to live with.'
I was on the point of crying at her, 'Don't you hear them?' The dusk was repeating them in a persistent whisper all around us, in a whisper that seemed to swell menacingly like the first whisper of a rising wind. 'The horror! The horror!'" (3.80-82)
That Kurtz’s last words drum repeatedly in Marlow’s mind reinforces the idea that words last forever.
Quote 2
"Kurtz discoursed. A voice! a voice! It rang deep to the very last. It survived his strength to hide in the magnificent folds of eloquence the barren darkness of his heart. Oh, he struggled! he struggled! The wastes of his weary brain were haunted by shadowy images now – images of wealth and fame revolving obsequiously round his unextinguishable gift of noble and lofty expression. My Intended, my station, my career, my ideas – these were the subjects for the occasional utterances of elevated sentiments." (3.37)
Even when deprived of his potential kingdom, Kurtz speaks with moving eloquence. But now Marlow realizes just how "barren" and empty his words are. His words are now just hollow reflections of his dreams "of wealth and fame" and his favorite adjective, "my," is meaningless. Kurtz owns nothing now that he has been removed from the interior.
Quote 3
"There were no practical hints to interrupt the magic current of phrases, unless a kind of note at the foot on the last page, scrawled evidently much later, in an unsteady hand, may be regarded as the exposition of a method. It was very simple, and at the end of that moving appeal to every altruistic sentiment it blazed at you, luminous and terrifying, like a flash of lightning in a serene sky: ‘Exterminate all the brutes!’" (2.29)
Kurtz’s idealistic and moving words change suddenly with this postscriptum. His condemnatory tone here blazes "like a flash of lightning in a serene sky" and sends a message far different from the rest of his report.