“By jingo,” quoth Panurge, “the man talks somewhat like. I believe him. But couldn’t we see some of ’em? I think I have read that, on the edge of the mountain on which Moses received the Judaic law, the people saw the voices sensibly.”
When Panurge talks about being on a mountain and hearing, he's alluding to Moses receiving the Judaic law on Mount Sinai. He claims the people "saw the voices sensibly." This is a clear biblical reference to the people of Israel hearing God via thunder and lightning. It's a climactic scene in the Bible, and the narrator suggests that with God, all things are possible. The passage uses this allusion to explore the tension between belief and the need for empirical evidence. https://www.goodreads.com/work/quotes/2663468-la-vie-de-gargantua-et-de-pantagruel