Matthew 3:12: "His winnowing fork is in his hand, and he will clear his threshing floor, gathering his wheat into the barn and burning up the chaff with unquenchable fire". Hamann's muse seems to take the place of Jesus.
The opposition to Kant (both, Kant and Hamann come from Königsberg) and the spirit of Enlightenment is clear. Hamann ist, so the title, writing about Philosophy (Aesthetics), but he starts with an evocation of the muses. Traditionally, philosophy is not protected by one of these ladies (even History is!), because it is not supposed to refer to occasions and inspirations, but to logos. So what does Hamann want? The reader has to go on.