The Death of Revelation or Zoroaster? Zero, Zilch, Zip!

So: spoke Zarathustra? No! 'Mum' was the word.
And since nada Z uttered, 'twas nada we heard.
Proving overly close-mouthed, as still as the grave,
Z vouchsafed us no greeting, not even a wave.

So: spoke Zarathuse-? Nope! I’d deemed the dude dumb.
Z turned tacitly tongue-tied: the word remained 'mum.'
Like his bouche (biding buttoned), his pie hole snapped shut.
All his channels of intercommunique? Cut!

So: spoke Zara-? Nossir! Not even a whisper
(preventing us learning if Z were a lisper).
Z's soundlessness smacked of the uber-laconic:
no sonorous speeches; no spiels ultrasonic. 

So: heard we Z sounding the word of God? Nein!
Nor no word of man neither. We'd nothing, in fine,
to show for our harking, our straining of ears.
Zoroastrianism's gone soft, it appears.