Approach To The Inmost Cave

We now return to Zarathustra for the approach to the inmost cave. In this book, Zarathustra leaves his followers to go argue with what seems to be the devil. I announce it as seems to be because he calls it the fire dog and says all others misrepresent him, his other descriptions seem to reference the devil, but it is never said for sure. The two speeches leading up to this both deal heavily in it leading up to the climax of the second book, causing the debate to be the ordeal, and the abondonment of his followers being the approach.
So now that we have established firmly what the event is, what can we question in it. The most apparent question is, why would Zarathustra decide that confronting the fire dog is worth abandoning the followers he worked so hard to gather. After all, all he did throughout the first book was gather his followers.
So, why would he do this? It seems the only possible reason is that he is sure the wisdom he will gather is worth destroying all his hard work. The speech he gives on hindsight of his debate is very wise, and shows a major change in thought, so that supports my reason. Fortunatley, though angry wiht him, his followers do come back to him, and forgive him for the third or fourth time he abandoned them.